I guess it's worth it, it seems that Mult posts often and consistently on the Patreon, once or twice a day most of the time, publishing polls, previews and demos.
-2.5$ is just access to polls, no demo.
-5$ gives you access to the game.
-10$ gives you a bit of anticipated access, builds with cheats and you can add a gal of your desire to polls.
Personally I think the 5 is the best bet for now, as the demo itself is the important part and later down the line you decide if you renew, upgrade or abandon the membership.