You would hope that a registrar would have better bandwidth and/or capabilities to protect against that then what you would generally have for your server(s).

You would.. but the business of being a registrar is bout managing zone records to be served out by the root/regional nameserver infrastructure, which your registrar may not even have much of a part in.

If they run additional business in hosting DNS, websites, email, and so on, as is common - that's really got nothing to do with the setup they need to act as a registrar.