I think most ESO players tend to fall into two categories:

1. Car Enthusiasts
For these players, each character is like a sportscar in a large garage of multiple cars and playing a character is like driving which ever car they fancy that day. Players like this don't need a class change token as they have one of every type of build depending on their needs. If you belong to this catagory, I'd suggest that you are probably wasting your time here and what I will be arguing will seem pointless and illogical.

2. Character Enthusiasts
These players have a main character through which they have experienced the world of Tamriel. Their main character is their Frodo, their Rand or their Geralt; and to swap them in and out whenever the convenience requires just feels wrong. These players generally spend most of their time on their one character and have a few alts. They have likely spent hundreds of hours (and thousands of crowns) on fashion and houses for their toons and have probably have some sort of backstory about how they wound up on Manimarco's altar at the start.

I'm the second type of player. My original character is a stam warden and I've had many happy memories in all forms of the game playing on this character. I'll never forget the first time taking down Molag Bal, seeing Vivec City (TES 3: Morrowind is one of my all-time favourite games), my first trial (Sunspire), first dlc hardmode dungeon (Bloodrot Forge), killing an emperor in Cyrodiil etc.
I've tried playing others but it just doesn't feel the same.

So I main on stamden, I play as a dps (I've tried healing and tanking but I just don't enjoy it) and I would like to complete trial hard modes on my main. Does everyone see where this is heading? So the bottom line is that while I can parse on my warden nearly as high as most other classes, I really can't pull my weight in newer endgame content. So it is unlikely I will ever get the thrill of completing this content and achievements on my main.

However, I think there are benefits to ZOS here in allowing class change tokens:

ZOS is leaving money on the table.
What I'm proposing is a class change token PLUS the ability to save different classes on the armory system.
I would be willing to pay $20 to be able to make a one time switch to one other class (provided I could store the original class and build in the armory). I would also be willing to buy a lot of additional armory slots to save this class and build in.
Am I the only person here who wants this? I suspect I'm not alone since switching classes on the fly is a standard feature on other MMOs like Final Fantasy 14, Throne and Liberty and... ummm... New World.
This leads me to a second issue.

Fewer complaints from players (including me)
Recently, how many times have you read in the forums about necro players who no longer want to play the game (or are taking a break) because their main got nerfed into oblivion? Do these people seem unreasonably upset since they could easily make a new character on a better class? Once again, if you are in category 1 (Car enthusiast) this may be the case but for Character Enthusiasts this is the equivalent of pulling Frodo out of Return of the King and replacing him with Poochie or Captain Marvel.
For people who don't play necro, sooner or later it will eventually be your current class that gets the undesired changes and your master crafter that you spent hundreds of hours on to get all the skyshards and story skill points is now a storage toon.

Long term player retention
Sunk Cost Fallacy vs Effort Justification
I've put in over 8k hours into this game! Yeah, played it pretty much all day and night during lockdown and never stopped since then. For much of this time I have not been able to commit to other MMOs because of the time and money spent but also the friendships I have made. Yeah, classic sunk cost fallacy.
If there is an opposite of sunk cost fallacy, I would suggest Effort Justification: the perception that the value of something gained is far exceeded by the effort required to obtain it. We saw this with the exodus of casual players who left when Oakensoul HA builds got nerfed*: suddently players who were faced with having to learn much harder rotations and mechanics in order to get the same dps as before and decided it was not worth it. This will eventually happen to the arcanist mains too.
Class change tokens could help in the latter case as the players do not need to grind out all their guild skill lines, skyshards and story quests just to keep playing the game.

Final Word
To the players who are Car Enthusiasts, thanks for reading all the way to the bottom and sorry if I wasted your time.
For everyone else, I hope I made some sense and articulated something we all feel.
To ZOS, there is serious money to be made here!

*PS: Yes, I know for experienced players that the Oakensoul HA build wasn't much of a nerf but I've seen a lot of casual and inexperienced players lose close to half their dps in content. For them the choice of git gud or play something else resulted in them choosing the latter.