Every single thing you have written there is wrong. That’s quite impressive.
There are many games where spending money is a gamble and you can receive nothing in return. This, however, isn’t one of them. At worst 10 summons will return ten 3* heroes, a useful addition that will improve any team, even if one only uses them as fodder.
To the larger point you are driving at, no one is compelled to spend a penny on this game. It’s possible to be competitive and have fun when F2P, which is pretty rare. Sort of the opposite of a “SCAM”.