Why not just use it as another primary. That way it isn't going to waste. Then you turn a mistake into more Beer. I think everyone (including you) would appreciate that.
I have used it as a fermenter but its capacity is 5 gallons which means that I can't use it for a 5 gallon batch without having the krausen blow off. I also found it to be much less friendly for cleaning. With my buckets, I have a huge opening where I can stick my hand in with a sponge and gently wipe the krausen ring off. The bucket all come with nice handles for moving them to the location I want for fermenting which is up a flight of stairs from where I brew. Have you ever considered carrying a full glass carboy up a flight of stairs? That heavy, fragile, slippery thing is just an accident waiting to happen. If I drop a plastic bucket I just get to clean up the mess of wort, no blood involved.