This would not be possible. Collection projects are simply a set of saved search parameters. A search is run when you load the project page and the project displays all observations matching those parameters. It’s essentially a nice-looking observation search that can be used for outreach. They are much easier on iNat’s infrastructure (for example, City Nature Challenge would be impossible at last year’s scale without collection projects and save users from having to add each observation to the project manually.
I’m not sure “advice” in quotation marks is necessary, it comes off as sarcastic and I think everyone here gave what advice they could, and with the best intentions. So please refrain from this kind of tone on the forum. If you have an issue with the way iNat works, fine, but there’s no need to disparage the contributions of people here.
That being said, users themselves can use the Batch Edit page to add their own observations to a traditional project in bulk. So the outreach on the project creator/curator’s part is to ask the user to join the project and allow you to see true coordinates of their observations in your project. If your goal is to get access to those coordinates, bulk adding the observations of a user who has not joined the project won’t help you. That’s the way the system was designed, anyway. Which is why I was asking for a specific example of how bulk addition by someone who is not the observer would be beneficial.
One possible middle ground would be the addition of an Add to Project section in Identify. Would that be helpful?