[h0h0h0h0111]

>Is this basically just putting someone on chain, presuming that there wont be a 51% attack

There is no chain or block creation. Also it's not a public permissionless network, so outside actors can't join for a sybil attack.

>I presume this timelock can be cracked early if I spend enough compute resources on it.

Sure like any cryptography, if you have more computing power than exists in the world

>Also I presume it doesn't work well for small time intervals (less than or equal to drand's block creation times)?

There is a dependence on transmitting shares between nodes in the network to gain a threshold number of share - right now each epoch is 30 seconds, but new networks could be created with down to ~1 second epochs