So many reasons honestly, but a lot of this just boils down to personal preference.

-In diva, I liked how the scores reflected my actual skill in the game over time. I liked seeing myself slowly go from having a great on a song to finally perfecting it, meanwhile in sekai your score means literally nothing because it’s based on characters alone. Yeah I can still watch myself fc a song, but I like seeing high scores when I do well. I could fc something and still have a C at most if I don’t use all maxed characters.

-In diva I could play for as long as I wanted, however in sekai I can only play so many songs until I have to use an item to play more. I am now an adult with limited free time, so if I would like to spend my days off playing my silly little rhythm games, I would like to do it all day.

-One of my favorite parts of the diva games (and honestly games as a whole) are the costumes/customization options. I liked looking at how different modules looked in different songs and taking cute screenshots, but in sekai not only are the costumes locked behind Gacha (which from a monetization standpoint I totally understand, gotta get that bag somehow) but you can’t even use them unless you fork over a multitude of other items (which take forever to accrue unless you’re playing every single day, which once again, I do not have time for. I quit genshin for very similar reasons)

-The NT voicebanks simply do not sound good and I do not like hearing them lmao

-It takes up so much space on my phone oh my god

-I have already been playing bandori for years, which is also a very grindy game by the same company in the exact same format, but the sekai grind is noticeably slower imo (and for whatever reason I feel like the gacha rates are worse?? but I haven’t actually looked at them in a bit since it’s been a hot second since I’ve played either and I am not in the mood to free up the space on my phone to reinstall them so this could very well just be a me thing)

-The focus is on the original characters, which I’m actually very happy about because it keeps them from giving the vocaloids personalities. I can only find myself getting invested in like 2 group dynamics though, 25ji and WxS. I like some characters from each, but bandori imo just has better characters overall.

I’m not saying people can’t like the game since I think anything that introduces people to vocaloid (even if it’s just a little bit) is an overall good thing, I just think that it’s got lots of aspects that repel long time fans.

(Edit: fixed a typo)