Realistically speaking, what does this mean for Ui's career going forward? The MV probably doesn't much influence her main career as an artist (though it does feature her illustrations), but it has big implications both for her streaming career and her musical career. I wouldn't be surprised if she's both getting offers to produce more music videos along with IOSYS as well as strong renewed offers from vtuber corporations (she turned down corporate offers before) to buy Shigure Ui and give her dedicated work in both the performing or production sides of the company.
In any case, she doesn't seem to be trying to leverage this to push her popularity as an indie tuber, since she's avoiding streaming, or she just thinks it would do more harm than good to the channel. There's a good chance she's focused on business negotiations. She's skilled in several fields of the industry, is a veteran with a lot of connections, and now has some big accomplishments and iconic IPs to her name. I'm guessing she gets a very lucrative contract working for vtubing corpo (or an even bigger corpo like Sony, as an investment in vtubing) or she's already so loaded IRL that making money isn't in her list of priorities to begin with.