if the scBTC can take advantage of faster tx times, why not?
miners would like it too as they'd get all those sources of income, tx fees from scBTC and sidecoin, as well as block rewards of sidecoin.
Because users have no interest for a sidechain with an additional sidecoin. Users will go for the more safe, most risk-averse chain which is the scBTC 1:1 peg model