Devs need money if they're going to add new landable planets, procedurally generated life forms, new ships, new stations, space legs and player buildable stations!
I support this, just so long as they keep working on the game in a meaningful way--beefing up the revenue stream from cosmetics is a great idea.
Ay, the key bit for me is this:
As always with our optional additional purchases, Arx can only be used to buy cosmetic Game Extras and will not be used to introduce and acquire pay-to-win purchases.
There could easily be shenanigans involved (Arx bought in cumbersome bundles only etc), but at the end of the day, it's fricking cosmetics. So long as it doesn't slide into P2W it's like the most benign microtransaction out there ¯\(ツ)/¯