I'm wondering when this game will be released on Steam. I wanted to buy this game because my friends invited me to play it, but I can't because I don't have both access to PayPal and a credit /debit card to pay for it.
You can purchase prepaid visa/mastercards at most gas stations/convenience stores that are one-time charge but can't be refilled if you only have cash or a normal bank debit card that can't be used online, but you inevitably will lose a couple bucks that you can't spend once it's almost empty unless you remember to take it to a store and use the exact last bit of money combined with cash for the rest. They also have an activation fee, usually under $5. I get your struggle, I still don't have a credit card and I'm 27 lol.
Steam takes a BIG cut and doesn't permit upcharging. It is a big expense for an indie developer who has to determine if the increased exposure on Steam will cover the added costs. Apparently these developers have determined that it will not. I guess they are in that sweet spot between being small enough to not afford the cost, and big enough to not need the exposure. So platforms like Humble, Itch.io, and direct make more economic sense to them.