With the new diversity of traits for vMSA weapons, it has become more difficult to loot good (BiS) ones. While you are guaranteed to get a weapon in the final chest, more often than not it is a Powered Ice staff, or other useless stuff like that.
Thing is, running the arena takes time. Assuming you can run it, that is. Not everyone can do it, and has enough time spent in-game to keep on farming it. And, from what I've heard from quite a few players, it's less fun than vDSA. (Keep in mind that vDSA weapons are great, but mostly needed for PvP, whereas vMSA weapons are a must-have to get the maximum out of your DPS in end-game PvE.)
Now before people go saying "l2p" or "if you can't run the arena, then you probably won't do well in end-game PvE", personally I did run it on my mag sorc. While I'm not on the weekly list since DB, and struggled for at least three months on the ice stage inb4 beating it, I have done about 200 runs in total to the present day.
Thing is, in all these runs, I've only got one sharpened weapon. Including my weekly rewards. It was a Lightning vMSA sharpened staff that I looted on my 2nd run ever, and man it was beautiful. In comparison, I own a dozen or so precise staves and greatswords, and 40+ powered weapons of all kinds.
As someone maining a magicka sorc and sticking mostly to PvP, a lightning staff was perfect. Unfortunately, one beautiful morning, I heard rumors, whispers in the wind of a certain bug allowing to reenchant your vMSA weapons while keeping the original enchantment. Having done damage tests with my numerous precise staves and convinced of its veracity, I did follow the somewhat dubious trend, knowing full well that it'll be fixed someday (which it was since then).
I was young and foolish, and thought erroneously that the RNG gods were kind and merciful, and would grant me another sharpened weapon since. Well the gods were cruel and, 198 runs later, weapon-less I remain.
Luck is fickle. Some people have it, some don't. Running vMSA takes skill and resources. Getting good loot however, is out of the player's hands. People who run trials can sell some gear and plunder from it. People who run vDSA have some BoE sets and have 4x more chances to get good weapons in the end, which are now tradeable in between group members. So why people running vMSA shouldn't make money of it?
While more often than not, dedication has no reward, in that case, shouldn't the option of selling your hard-earned weapons exist?