Major technical difference is no access to the filesystem. Its a dealbreaker for me.
Unix = everything is a file.
You get /var/snap and thats it. So you cant write an editor for example.
No access to /proc to check memory usage etc etc.
Also the permissions system is really stupidly restrictive, and worse its getting more restrictive not less.
Like that kernel fiasco recently where linus had a rant about sectypes breaking stuff by default. Snap is tha problem multiplied by one thousand.