Recently, there's been more talk about whether re-staking and shared security are just "profit stacking" schemes. I find it pretty annoying but can understand it too. The point about LST earnings mainly comes from the staking rewards themselves; what you get is a "certificate," and later you can stack it with other projects. The extra part is often a subsidy provided by others to attract you to offer security/liquidity, or risk is bundled and sold to you.

Don't pretend not to see the risks: one layer is signing/authorization—click "agree" once and you might give away the transfer rights of your LST; another layer is bugs in the protocol itself, governance chaos, or shared security issues that could cause a collective loss; a third layer is liquidity—when you really want to withdraw, you find the slippage is ridiculously high. Anyway, whenever I see yield stacking, I first ask: who is paying for this yield, who takes the blame if something goes wrong, and how many confusing authorizations do I need to sign... Think carefully before clicking, or you'll end up with a "souvenir" in your wallet.