If you deposit a check electronically, such as using mobile deposit, you will still have a physical copy of the check. Your bank will process the image of the check as if it had the original.

Someone could endorse a check to you as a third party payee. If you receive a check that is endorsed to you, the original payee is probably going to have to be present for you to cash the check due to the high risk associated with accepting these checks (it is difficult to verify if the original payee actually endorsed the check to you, or if the check was stolen).

It is very difficult to verify if a check has been cashed or not because of the possibility it has already been deposited electronically.

IMO, your chances are better of being able to buy one as a novelty versus being able to buy an uncashed check. Most banks are waiving check cashing fees to cash these checks, so whoever the check is made payable to has no reason to accept anything less than face value, and you would have fraud risk in buying one of these checks.