That is a good point. I think I get what he is saying. Which of this giant pile of games is still good even if you just money power your way to the end. It is also kinda subjective.
Probably the only way to know that would have to been on the receiving end of that game at the time? Basically trying to actually really manage your real money so you didnt just blast it all on one game?
For example I know Terminator 2 is fun. You most certainly need a decent amount of quarter to get to the end. Usually took me a couple of bucks. But the cab was part of the fun in that one.
I know simpsons can be pretty fun to just play through. You pretty much ended up plowing at least a buck into the thing to get anywhere.
Double Dragon, streets of rage 2 can be pretty good too.
Heavy Barrel and Time Soldiers I never got very tired of those and just kept feeding them money.
Cadash can be fun to power through also.
Something like time pilot once you go through all the stages you have seen most of what the game has to offer. At that point it just gets progressively faster until it bumps you off. Most of the early 80s games were of this type. Try to look for games where there is a clear 'end'. Like bad dudes. These were more common in the late 80s early 90s.
Just remember most of these games were meant for you to be off the machine in 5-10 mins tops or at least dropping more money at that time. So the longevity gameplay is going to be fairly shallow.
Also look to the emulator info/history text files. Many times they have similar games if you find one you kinda like.