Yes, sidechains benefit from bitcoin but that doesn't mean anything if a small group of the userbase has outsized control over token issuance.

Bitcoin's weakness relates to reorgs and its slow, broadcast propagation pattern. Lightning's weakness is griefers and expiring/stuck channels.

I don't think what bitcoin does is at all similar to LN. There is a much weaker consensus in LN, because it doesn't have to share the state changes, only the p2p information for generating paths and a summary at the end of each channel, the security problems for LN come from mischief with channel partners and channel liquidity.