BitDefender on OSX is terrible. I wouldn't recommend it to anyone for any reason. It often thrashes the CPU, increasing heat, battery usage, and obviously having a massive impact on disk performance on overall system responsiveness. I've never used it on Windows, and likely never will. Windows Defender has always been fine for me on Windows, I've tried McAfee etc in the past, and they've all been much more trouble than they're worth. I can't deal with the massive performance loss, and strange abnormalities that often impede software testing brought about by AV software meddling in the filesystem and network layer.
There's a reason so many otherwise useful programs try to smuggle AV onto your machine unless you happen to notice it, and opt out. It's because nobody would willingly subject themselves to that.