I agree, but SSE is a more complex protocol that requires additional handling on both client and server, with capabilities that may not be relevant for your use case (multiple event types, event id). For JS clients and JS servers it is not particularly onerous to implement, but for other ecosystems can require a fair bit of code. JSONL streaming is very easy to implement on both ends, so all else aside I think would be preferred if all you really want to do is stream JSON values.