Snap is like using a python virtualenv, while apt is like using global pip. We all know which one of these usually results in a broken installation.
Apt debs more often than not rely on some specific version of a third party package which becomes a headache when there's another package that needs a different version of it. Snap in theory solves that, making the deps local to the package you're installing.
If I had a dollar for every time I had apt bullshit me with "requires package, but it will not be installed" or something of the sort I'd probably have something over $20 which isn't that much but still infuriatingly high.