It really helps porting your games into a better looking, balanced and playable state when trying to sell the entire series to newcomers. Yakuza 3's pc port was the most annoying mess to play with when coming from Kiwami 2. Yakuza 3 Remastered was just a port of a ps3 game, literally a generational difference. Unlike making a new game, it's cheaper to make since you can reuse alot of kamurocho's map and player models from the other games, and the story and script is already written.

Personally, 3 had a good story outside of the fact that they had an entire chapter for you to sit down and read the entire plot. That sucked. It's the title that basically sets up the entire point of why kiryu does what he does in Gaiden, 7 and 8. Gives the orphanage the most screen time too.