my assumption is that the sidecoin, whatever it is, may offer features with greater appeal than Bitcoin itself. scZC is a good example as it might give perfect anonymity. and if it's paired with faster tx times for both scZC and scBTC, then yes, alot of ppl should be attracted to it including miners. especially if the block rewards are being given out in the form of scZC.
But sidecoin with feature is competing with scBTC with the same feature, greater market acceptance, more liquidity, bigger network effect.
Sidecoin reintroduces risk of greater volatility, sketchy distribution and likely inferior network security.
Sidecoin = altcoin