Lido is a secure liquid staking solution for a number of reasons:
- Open-sourcing & continuous review of all code.
- Committee of elected, best-in-class validators to minimise staking risk.
- Use of non-custodial staking service to eliminate counter-party risk.
- Use of DAO for governance decisions & to manage risk factors.
Usually when staking ETH you choose only one validator. In the case of Lido you stake across many validators, minimising your staking risk.