But, at least the way I was doing it, it's not adding any security as discussed here, since you're doing everything in the VM so anything in the VM has access to everything just as if everything on the host anyway.
What they don't have access to is my actual desktop, nor yesterday's snapshot of the VM desktop.
It's obviously not as fast as running GNU on bare metal, but it's fast enough for text work.
I guess this is where we set the bar in 2019.
I'm not GP commenter, but certainly what I do for a living is browse the the internet and edit text files.
For me, the VM was my entire machine. (It wasn't meant to improve security, it was purely because I wanted Linux but couldn't have it on the host.)
I wanted GNU tools and environment, and I also wanted to not have to install Linux on the Apple hardware, because I don't have the patience for that.
Meanwhile, my desktop remains clean and ready to play media in native environment with good hardware support.
I used to think it'd be slow, until I tried it. My computer is 8+ years old, and it works fine. I mostly do text work.