I don’t think that snapd package could keep being available in EPEL if we start bundling libseccomp. On top of that, making sure that copy of libseccomp is bug free would become package maintainer’s problem.
Note that libseccomp in CentOS7 comes from RHEL7 and we have no control over what is in the distro. AFAIK RHEL7 is in maintenance mode, so I would not expect any major changes or updates, other than really critical fixes to be pushed into the repositories (which implies the same for CentOS 7). I would still suggest updating to CentOS 8.