The main benefit is reducing the incentive for the developers to steal. If you know 90%+ of the funds will disappear before you can do anything then it's much less attractive (where the alternative is making money by fees over time if the protocol is successful).
The risk needs to be balanced with the risk of funds lost because of a smart contract bug that can't be fixed. Different projects make different choices here.
Typically projects like this start with "training wheels" like this at launch, and gradually increase the timelock delay and / or move the control over to a dao to control.
People doing esoteric DeFi are tapped in much more often than that. I'd agree in a broad general use case it's not enough time, but for DeFi as it is today, it's plenty.