Yes, I'd say there is something misleading or logically wrong about this quote.
Stream and download as much as you like, with a dedicated fibre connection direct to your home
When it says "Stream and download as much as you like" it implies more towards having an unlimited bandwidth and it has nothing to do with whether we have a dedicated fibre connection or not.
Mostly all packages nowadays whether copper, hybrid or wireless has unlimited bandwidth. So by this logic we can all download and stream as much as we like, we don't exactly need full fibre for that!
BT should be conveying the actual benefits of a full fibre connection and from a marketing point of view, this slogan or quote is somewhat weak as it doesn't really convince the consumer why they should switch.
A better slogan or quote would've been "Stream and download worry-free from disruptions with a dedicated fibre optic connection direct to your home".
There should be a compelling case and a better advertisement to convince the consumer why they should switch to Full Fibre. For example a quicker, lower latency or reliable connection (no drop-outs) in the middle of your online gaming or let's just say during your live video streaming so you can have a frustration-free experience. No more freezing and buffering issues to worry about ever again!
I'd say the most important reasons for wanting Full Fibre are having a more reliable internet connection that doesn't drop out, having faster symmetrical download speeds and having lower latency are the strongest reasons for wanting a dedicated fibre connection.
Not many people are informed of these benefits, most layman users will say, "Oh I'm happy with FTTC, what's the need for FTTP"? "I can still download and stream as much as I like with FTTC"! That dedicated fibre connection should be followed with an explanation of its actual benefits and this slogan/quotation doesn't do that.