To be honest i have some mixed opinions about stuff like this, regarding this generation of games and consoles, with mention of nintendo switch getting a mario kart port, smash bros port, zelda breath of the wild (Maybe can't call it a port, i dunno) Then they got Final fantasy 10 HD ports... to ps4, the kingdom hearts 1.5 HD and 2.5 HD port to ps4, MAJORITY OF PSVITA GAMES ported to ps4 and such, is kinda nuts.
One thing i do like is on psn there is some games that has the branded motto of "Cross buy, cross pay, cross save" Where you can buy a game on playstation store, and get it for all available systems (PSVITA, PS3, PS4, PSP) as examples. But not every game gets this privlage of saving you money and require to buy it all over again to play on another system.
But stuff like Ultra street fighter 4, Devil may cry 4, Marvel vs capcom 3 on Playstation store, or maybe the Zelda wind waker and twilight princess HD which add some things to the game, like fixing previous issues with the game, added new content or features to give variety or just adding all previous added DLC that you might already have but find it unnecessary to get again. A upgrade adds new stuff that wasn't before. The HD collections of Kingdom hearts and final fantasy 10, Zelda wind waker and twilight princess adds new content, stuff we didn't have anymore, the main selling point isn't that is now in HD or better framerate.
I mean how do you feel about that, knowing i have both Kingdom hearts HD on ps3 and then have them wanna sell it on PS4 But offer no actual difference, same 1080P graphics, same performance and features. I can't tell the reason for this, i guess is not aimed at me, the difference in some ports are very small and not worth what could be consider upgrade but is probably more for people who doesn't have it or give them a reason to be interested by adding another game to a already small library for the console. But i'm asking normal people like me about the opinion. Every consoles main selling point is the exclusive content i thought.
You wish maybe you had waited longer before buying it, or you not regret this decision, or maybe even just will sell it and get the upgrade? I honestly never sold any game i owned, but is just me. I'm not some collector, i just can't part with stuff i worked hard for.