TL;DR either way there's a timezone conversion, just look up your time in relation to ET, no different than you looking up your time in relation to UTC. Plus, on the forums they post the times in ET and UTC for maintenance, since the game creators are in ET time zone it makes infinitely more sense for them to just base everything off ET especially since one of their major servers are in that region.
To add a bit of personal experience, I can say, that when there was a need to coordinate any activity (in eso or in real life) with people from other time zones, there was never a talk about local time zones and their names. I don't know the names of other time zones, I don't know even the name of my time zone, because it doesn't matter. The only thing that matters is what UTC offset is used. If one person is UTC+A and another is UTC+B, then the time difference is (B-A). What are the local names of these offsets nobody cared.
Australia's even more messed up with daylight savings, it's very confusing.As a quick aside the USA isn't north of the arctic circle. With the exception of Alaska the northern border of the US is basically in line with central France. From what I can tell the d in EDT is referring to when the eastern time zone in the US enters daylight savings and each timezone in the US has its own equivalent.
Fun fact, this is true except for the state of Arizona. They permanently go by standard time and do not observe daylight savings. We're weird here in the states.