As a whole, no. There are some scams out there, certainly but the biggest risk is generally that the platform doesnt get built, doesnt work, isnt adopted by a critical mass, etc.
About 90% or more of these platforms dont or wont get built, either because they lack access to the talent, they pivot, have a bad team, run out of funds, fail to prove concept all the reasons any startup fails. But that doesnt mean they acted nefariously.