the agility of lighter wheels will become apparent.
or perhaps the skittishness ?
"just imagining the speed i could go if I was always accelerating"
That would be the same speed as you can go, spun out, in your fastest gear, or faster, if gravity assisted.
it goes without saying that to be always accelerating you'd need some other source of motive power than pedalling, and I imagine avoiding obstacles will become harder as you approach the speed of light...