Because I am pretty sure it isn't true. I am one of the few people who used bitcoin on steam during this time and I don't remember it ever being instant. I would like to see clarification to the top point because I don't think it is true...

In my opinion when he says "fraudulent" he is probably talking about how people would use it to avoid bans. Steam would track banned users that remake accounts by checking their CC. They would also verify the people by making sure the address on the CC was close or the same to the address on the account.

With Bitcoin you could avoid any tracking from remaking an account which leads to more 'bad actors' using Bitcoin. For reference you needed to spend something like $5 - $10 to enable trading on the platform. From their people would phish, scam, and break the TOS on the account.