Sure. To be honest, I might disagree that it is uncommon. I can also point to a specific example that I just looked at in a pdf that is publicly available.

Here is the pdf:
https://www.sfcg.org/wp-content/uploads/2014/02/designing-for-results.pdf

If I go to the second page, there is a link to the home page of the creator of the document, as www.sfcg.org.
In Acrobat Reader Pro DC v22, it can be clicked with the arrow tool.
https://drive.google.com/file/d/1TisruGGGD17woiW9HGEiRpsofGOEX6MJ/view?usp=sharing
I feel like almost any url is clickable in Acrobat, but I am not regularly checking if it is automatically making links like a browser or if the ones I want are all set as links in the pdf.

For the same link in zotero reader, I don't know how I could click this link.
https://drive.google.com/file/d/1_ZdLd2CvWZljky4qVQ_DtQbpNXc6q4K1/view?usp=sharing

nifty :)

Thanks again for all the work that goes into zotero ~

Nice --
thank you!