That of course is the $64,000 question.
This answer has to be looked at in multiple layers.
First, fact that something has been "remastered" does not guarantee that it is better sounding. There are many variables in the mastering process. Is the equipment used to remaster the album better sounding that that used for earlier releases? Just because something is newer, doesn't mean that it is better (how many tube vs transistor discussions have we had. Mastering is a personal thing. What is the talent level of the engineers doing the older vs the newer masterings? And of course what is the source for the remastering and if is is the same original master tapes, how have they aged and has there been any degradation over time.
Secondly, one of the differences in remasterings of particlarly vintage jazz and classical albums from the 50s and early 60s is related to the playback equipment available today. masterins done in the 50s were done with an eye to the tracking ability of the TTs and cartridges of the day. I know of several albums (the one that immediately comes to mind is the Reiner/CSO Pines of Rome) that the masterings had to be restricted in terns of amplitude and frequency in order keep them from mistracking. Remastered today TT design has improved to the point where these albums can be mastered to contain all that is on the master tapes.
Third, IMO a lot of the differences in newly remastered versions comes from the modern vinyl formulation, heavyweight pressing, and in some cases the new flat vinyl profiles. So totally separate from the remastering, the modern physical LPs have the potential to sound better that the older pressings from the point of view of the physical disc alone.
All that said, I have remasterings that sound better, worse and no different that older pressings of the same album. Slapping a remastered sticker on a re-release provides up with the assurance of nothing more than some extra marketing buzz.
So that leaves us with your last question, assuming that a remastering does produce better sound. does that better sound lead to more enjoyment. That I would say is a very personal thing. If you are most concerned with listening to the sound then the better SQ for you would be its own reward. But for those who are more concerned with the music itself the question becomes how good is good enough? (I am not passing any judgement of people who value sound over music or music over sound. People get into this hobby and get pleasure from different aspects of it. neither is inherently right or wrong. I am just saying that different people will look at this question from different angle) Just speaking for myself, I have a certain threshold of SQ that will allow me to forget about sound and focus on the music. While I can appropriate higher levels of SQ, I can still get pretty much the same level of enjoyment at my "threshold" level of SQ. Some people could not live without a $6k moving coil cartridge while others are perfectly happy with a $75 Grado. Whatever floats your boat. Of course the other factor on if the new version brings you musical pleasure is what you have right now. If you have a beat up LP from your high school days the decision to upgrade will be much easier than if you own last years 200g release.
This got a lot longer than I planned. hope it helps.