It have a lot of lag, but it depends on the video and all the thing it envolves like format and quality I guess, I've realized that you can change the gateway on the IPFS setting and it'll work for some videos, I don't know what it means and what it does, i'm not a programer or developer, I think it will be really helpfull for users and steemit itself if someone can explain all of that stuff in an understandable way.