snap provides a form of containerization, if you talk about something like Docker, snap is significantly simpler because it's a container for an app rather than a container effectively for an entire VM.
Practical example, I use nextcloud as a snap, which requires basically one command, it self updating, shares the same IP as the host whereas each docker container would have a separate ip. If you only want to isolate an individual application on a host system (which is a common use-case) most container technologies are overkill.
