I'm not really that familiar with Sonic 3D Blast, but trying out the new DX beta, I find it weird the way Tails and Knuckles continue to take your rings even after you've visited their special stages. Maybe they're storing your rings so you can't lose them or something? Or is there some additional reward if you give them enough? I just find it really confusing. It also might be nice if they only took the amount they needed to open the bonus level, rather than all of them.
Of course, if there's a reason they behave the way they do, feel free to ignore this.
At the very least, there's a conflict for the player who wants to give Tails/Knuckles enough to reach the bonus stage but not any more than that, which has theoretically existed as long as the game has, but is exacerbated by the presence of Super Sonic. A player might want to both visit the bonus stage and become Super Sonic in the same level, which currently means they'll need to carefully avoid collecting more rings than necessary in order to prevent "sacrificing" them to Tails/Knuckles, before restarting their collection in order to become Super Sonic.
Phrased differently, what is the upside of having Tails/Knuckles take all of your rings immediately? It's slightly more convenient if that was your plan all along, but you can always talk to them again to hand over more rings, whereas if your plan was not to hand over all your rings, tough, because you already did.
I don't really see a clash. Once you collect all of the emeralds, you essentially have the choice of earning lives through special stages, earning lives through 100 ring collecting, or using Super Sonic to gain invulnerability but lose the ability to gain more lives. In regards to gaining a higher score, you have the option of boosting the Knuckles/Tails bonus, keeping the rings, or using them on Super Sonic to potentially get a better time bonus.
Thread can be moved if so desired.
I think the addition of Super Sonic makes this feature kind of clash with the DX version's gameplay. There's a conflict between the idea of keeping rings (now desirable since Super Sonic exists) and handing them over to Tails/Knuckles. Perhaps Tails/Knuckles could take only the amount necessary for the bonus stage automatically, then have any further visits ask the player if they want to hand over their rings? Or always ask, but again only take what's needed on the first visit?
Feature Requests should not be in Bug Reports.
They give bonuses at the end of the stage which helps with building the score up.