Sidechains are there to create new applications/features that are not possible on the Bitcoin chain. There's no reason why you would create a sidecoin on top because it defeats the whole purpose of the 2wp.
Unless that is the reason.
An inferior shitcoin will defeat the superior option of risk-averse 2wp?
Do you realise what you are saying here?
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.