Staking your cryptocurrencies on the Meria platform means that Meria holds your cryptocurrencies and takes care of placing them on an on-chain validator. Using a centralized platform allows you to use a simpler interface but involves higher fees to compensate the intermediary. The chances of being eligible for potential airdrops are also lower.
For more information, check out our article "Staking On-Chain or on a Platform: How to Be Eligible for Airdrops?"