I'm not sure that using Google Maps to demonstrate copying a single way of encoding coordinates vs using an open standard is a terribly convincing argument.
Having a field that takes lat and lon has all sorts of ways to enter data either incorrectly, or in an unexpected format - if someone has coordinates from some other source they might be typing it in, rather than copy/pasting.
Also, as others have mentioned - plus codes (or Open Location Codes) are an open standard that can be implemented by anyone under an Apache 2.0 license with a whole bunch of example implementations on github[1]
Having a field that takes lat and lon has all sorts of ways to enter data either incorrectly, or in an unexpected format - if someone has coordinates from some other source they might be typing it in, rather than copy/pasting.
Also, as others have mentioned - plus codes (or Open Location Codes) are an open standard that can be implemented by anyone under an Apache 2.0 license with a whole bunch of example implementations on github[1]
[1] https://github.com/google/open-location-code