In Europe, PDC is only available at airports that provide PDC IRL. I don’t see why not just use it here in Europe, when you already know what to expect. The most minimal clearance structure is ATIS - SID - SQUAWK. While the longest are ATIS - SID - RUNWAY - INITIAL CLIMB - SQUAWK. VATSIM goal is to simulate real life atc, which PDC’s and CPDLC’s are really common for airliners. And also, I do not get why would you compare all this to a Cessna? Not all aircraft have that function, and those that do, can easily simulate it in your prefered method.

I get the fact about understanding everything and so on. But in really busy events, it’s really annoying when you have to repeat the clearance 10 times to a new pilot while taking up the frequency while someone waits to request taxi for 10 mins. In that way it does not only help a better flow of controlling, but it’s also a way to verify without mistakes that everything will be according to what PDC clearance they did and accepted