I'm in this boat. I had rollers in the "pre smart trainer era" and I personally can't say as though they really helped me do anything better. Balancing on rollers isn't remotely close to riding in real life unless you somehow have a hyper-sensitive bicycle (?) As someone that can do a track-stand as long as I want on my bike, I didn't see any improvement in balance from using rollers or even view that as a problem to be solved?

A smart trainer was a game-changer for me as it controls resistance, something I couldn't control on rollers and likely wouldn't control even if I could. The thoughts of doing an all-out sprint on rollers sounds like a recipe for disaster, not to mention one's power output would be radically limited as one would quickly "spin-out" if the roller resistance didn't increase radically and quickly, and then one would have to deal with tire slippage (among other things).

I could see using a portable set of rollers for a pre-race warm-up, but beyond that, I'm hard-pressed to find any advantages to rollers over smart trainers (+ an app like Zwift).. especially now that the price of smart trainers has come down to very affordable levels.