I used SJ's forums a LOT when I used to try and make my Pokémon comics there, the only reason to lose it is the same as so many other sites - splitting the fanbase to make it more "digestible" for people who'll visit and never engage. Same for removing customization options.
Honestly, it's always been the third place with some benefits, if it does this I don't think it'll last. Tapas and Webtoons are already the place for comics with a homogenized layout, why would you want a third mirror that's inferior in every way? I can tell you the Tapas url to my comic right off the top of my head, not so much trying to spell Smackjeeves if I can't write it down, for starters. This also sucks to a LOT of comics that I read that have custom layouts without having to pay for a Wordpress domain, which only harms everyone involved.
Also, when do these updates roll out? Two weeks. Independent creators don't have time to scrap up money to buy a domain in that time and/or move EVERYTHING to another site, but it sure looks nice on the yearly report, doesn't it?