Registering a domain usually happens very early in a business' history. It might literally be the first concrete thing the founder does. If the founder is non-technical, they're just going to Google "buy a domain" and see who comes up.

Do it, now. What comes up?

Yes, once IT gets professionalised, they should switch to a better provider. But the registration will likely be for multiple years, with auto-renewal, and when nothing has gone wrong, theoretical problems take a backseat to live ones.