I agree with nearly everything except your point (1).

Periodic polling is awkward on both sides: you add arbitrary latency _and_ increase database load proportional to the number of interested clients.

Events, and ideally coalesced events, serve the same purpose as interrupts in a uniprocess (versus distributed) system, even if you don't want a proper queue. This at least lets you know _when_ to poll and lets you set and adjust policy on when / how much your software should give a shit at any given time.