For GUI apps I think yes, videos too are helpful too. One downside, with Nostr moving so fast, is keeping them accurate when software updates.

Screenshots are pretty helpful for pointing at buttons and guiding the visual reader. Sometimes a picture is worth a thousand words after all. Sometimes diagrams are helpful too for visualizing mental models.

Yes. Or even litle screen-captures. Really drives up the maintenance effort, though, as those things tend to age quickly.