of to have the video embedded in the post you have to upload it to d-tube, also remember that not all frontends support the embedding of an IPFS video but busy and steempeak do (actually maybe steemit does but i don't use that much) -- if you just use the url then yes, it just posts the youtube video embedded which is native everywhere and pulls in the posts description instead of you having to add a picture and some text. i think i answered what you needed.