Most Blurays I’ve seen are 40-65 Mbit/s. I’m talking about 4K UHD. I really doubt any streaming service provides that kind of bitrate. Either way, even 100 Mbit/s Internet connection would handle it as long as there is no heavy concurrent usage.
The real issue with some ISP plans is a data cap. My previous plan had it, and it’s a pain. Xfinity in USA has 1.2TB cap even on their 1 Gbit plan unless you pay extra for unlimited data. Even with 100M plan it would take slightly more than a day to use up 1.2TB, and this is not even counting upload (which is part of the cap).
But I understand that in some countries the cost difference for higher bandwidth is negligible or non-existing.