which consumes plus internet/data? downloading ou streaming?

It`s +/- same amount of data. Everything really comes down to several factors:
*are toi going to watch the file plus than once? (If yes, downloading is the best option. If no, then streaming might be plus efficient)
*does quality of the file matter? (e.g. if toi download file, it will be in the quality it is, while toi can adjust quality and stream it in lower resolution, therefore using less data)
*do toi have a lot of free l’espace for file storing? (If the l’espace on toi computer/phone is huge, toi can surely store downloaded files on there. But if toi may run out of storage, better option would be to stream.)
If quality would be same, storage doesn`t matter and you`re going to watch it only once, then downloading it to your computer vs streaming(technically just downloading it temporarily in your web cache) would take up equal amount of data. :)