You're kidding me... No, I did not know that. I wish someone told me that sooner. I placed a bet with that free $50 literally seconds before reading your post. I went for a game with x1.15 odds lol, what a waste...
Live and learn I guess.
I know the feeling. I thought just like you when I was a newbie punter a long time ago and regretting wasting a big freebet on such low odds. Freebets are only worth it if you use them on high odds bets.
An even better approach is to arb freebets(Matched betting) though this could you limited later on.