It's not so clean cut. For a web browser, I think it's better to ask the user to share location data so that you can use that to make their experience. They would do this using the methods you suggest.

I think the risk here is the assumption that the only devices where you may care about GeoLocation are ones that have this capability. There are cases where using the less precise GeoIP option is not only legitimate, but it's the only option you have. What about IoT or embedded systems where you may not have the capacity to determine the location?

You can't treat the data obtained from GeoIP databases as being absolutely precise. However, for most cases the data will be precise for most people's needs.

I'd be interested in hearing how you handle devices that don't have the APIs you mention.