Videos are one of the most important parts of marketing projects. Github projects without gifs get less attention. Humans are visual and don't like scouring through a readme before seeing some action first.
Read me says: > "Hello everybody out there using minix - I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones"
Now, I'm not so sure it would succeed if no nice visuals.