Personally I've enjoyed racking up ~800ish hours over the last ~5yrs while spending on my own dime and going to destinations of my choice.
What I enjoy about it is that I am the one doing all the planning and flying; every one of those flying hours after the PPL check-ride is real time at the controls making all of the decisions (helps that I don't have an AP so I can't just take off and zone out

).
I also see value in
going to new places. New airports, new airspaces, fly around new terrain and talk to new controllers. Just encountering new experiences and situations is valuable IMHO.
I could be mistaken - but that seems a lot more useful than riding right seat with a rotating cast of newbies. I would *hope* that IRL as a professional ATP that your primary job is not supervising the captain and grabbing the yoke when he's about to kill you both, while flying the same approach and landing at the same airport for the 1000th time. Then again it seems most pilots take the CFI route and our collective air safety record is pretty solid, so maybe there's something to that method of development.