Ephemerals are not stored on relays so you must be online to receive them. Fast and save space.
Replaceable events are stored but a newer event will remove the old one so the space used is about the same. No need to be online to get those events.
Discussion
Can you give an example of an ephemeral event please?
ephemeral and replaceable one seem to make the most sense. Songs change so often, that there’s no need to really cache them, I guess.
I’d love there to be a small green text going from right to left showing “Currently listening: ____” and on the left of it there could be like a sticky Spotify logo 🤔