I think they have some potential in allowing us to have more privacy related options as part of bitcoin, and letting us test out upgrades to the network that are taking years to build consensus around and adopt.

I worry though, because the social effects and economic effects that it will have are relatively unknown; it will likely trick a lot of people into thinking it solves things like scaling by introducing sidechains that have big blocks that nodes can't keep up with. It could justify ossification of bitcoin to a greater number of people making it even harder to change, its a guarantee we need a hard-fork at some point to fix a time stamping issue that *will* cause bitcoin to grind to a halt; its also a guarantee that bitcoin needs improvements in how well it utilizes block space, things like cross input signature aggregation and covenants, these could be added to a side chain of course, but if bitcoin grows to a billion users then it will be impossible to get out of that side chain because we aren't prepared to handle that volume on bitcoin.

I don't see a right answer to drive chains, only that there is critical work to be done on other upgrades and we should let this stew for a bit.