I think this is a great way of doing it for a game which is getting updates all the time. This isn't the type of game which is gonna get a big expansion for a fixed price, because it would split the player base.
I was already hoping for a way to financially support the game, and I think it's awesome they are also going to give credits to server hosts, streamers, players and the Ocean Cleanup.
And it is in no way pay to win, so that's a huge plus.
The only thing I'm not entirely positive about is the fact that you can give/sell the skins you buy ingame to other players. I would have it that only the one who bought it can use it, because this might incentivise players who have spent a huge amount of money on skins to "resell" them together with the corresponding items, as a marketing stunt.