What problems might I run into if I don't create new non-default service names for my PDBs?

Oracle 19.7 on solaris, converting to multi-tenant.

We've always used the default service name to connect to our single instance, non multi-tenant databases. Now that we're converting to multi-tenant, and I've been doing some reading, I've come across the statement a few different times, that we shouldn't be using the default service name. ie. from the administrators guide: "The default service has the same name as the PDB. You cannot manage this service, which you should only use for administrative tasks." and "Oracle recommends that you not use the default PDB service for applications."

I also found a similar statement in Mike Dietrich's blog: