Yes of course, you will get the benefit of some of the toolchain fixes when building on your target platform, but there are also patches that are maintained by the distro (be that Ubuntu or Debian or …) to the build scripts and even source code of the packages which should be carefully considered.
To be clear, I am not advocating that snaps should be a straight copy of their corresponding debs - perhaps incorrectly, I assumed that OP was asking about dependencies.
I do think that, where possible, dependencies for snaps should be first sourced from the Ubuntu archive to get all of the “Ubuntu goodness” that has been baked in to the packaging, and I can benefit from the work already done by existing Ubuntu teams. e.g. if I’m snapping software that depends on PostgreSQL, I do not compile PostgreSQL, since it’s already packaged. This means the Ubuntu Security team can notify me when there’s a CVE for PostgreSQL (see Snap updates and developer notifications on security updates ). I get to concentrate on building /my software/ and encoding it in snapcraft.yaml whilst leaning on Ubuntu maintainers (and upstream) for my dependencies.