It's not just a problem with early access - it's a problem with people being able to play the game at all, period, regardless of whether or not they've even bought Endwalker. The rest of the game doesn't go away because there's a shiny new piece of it, and Endwalker doesn't have a separate login process. This isn't just compensation for not being able to play EW, it's compensation for not being able to access the game consistently or in some cases at all.
I mean it definitely is 7 free days in addition to the sub, even if it is also compensation for time lost, but. Yeah. It's not just early access people dealing with these queues and errors.