The "3 landings/take offs on type" in 90 days thing*. ie "recency"
Opsman, I know what you're saying but some people will view the endorsed pilot with no other flying since the rating as now out of recency. This isn't as applicable for someone who's let's say, flying around in a turboprop and buys an eg 737 rating. They are still flying in 2 crew/IFR environment. However, the low houred person who's bought a rating and isn't flying at all will rapidly go out of "recency" and while they may be technically "current" they will have forgotten a lot in 3 months and will take time and money to get them back up to speed.
It's just something else to consider before handing over a large amount of cash.
*for a captain. For an FO it's 1 take off/landing in 90 days.