If you mean, that they can only earn 0.5 TON and it looks very cheap, you are wrong with that. First, they are not only earning that on one to two users but if many are doing that, combining each 0.5 TON can already go a long way. Secondly, they might have access to the users whole wallet once they initiate the transaction, so they can steal more money.
I'm not saying that they can only get 0,5 TON, and it has a very cheap price. 0,5 TON is currently worth close to $3, and that's a relatively high value. The projects we are discussing here have a lot of users, so if 0,5 TON is accumulated, it could even reach a million dollars, so you're wrong about your view of me. On the second point you're also wrong, there's not a single project that requires a direct wallet connection, so on-chain theft is impossible, at least until now.