Sure, if you have such a dongle, and it has sufficient view of the sky. Adding a 'free' https based sanity check on top of NTP seems like a good balance of cost vs reward.

gps (and friends) is a nice way to get access to a very accurate timesource, but it's not always worth the cost.

GPS doesn't send full time. It wraps every 1024 weeks, or about 20 years, hence you need a (very) rough basis in case the system is over 20 years old.

Or run their own NTP server. That's what I do in my home network.