PoW and difficulty adjustment, limits number of blocks per 10mins in a fair way. that's the point. also it enforces the order.

this can also be used to make timestamp based non-monetary aggregation of call events desenterlized.

preventing timestamping spam (number of timestamped things that needs to be downloaded off-chain for verification).

limiting the number of timestamped events per block fairly. without a centralized aggregators or sequencers. creates a fee market for event timestamping.

i guess, idk. maybe i have been thinking too much walking around the house missing something critical.