You can see the difference between Blu-ray and streaming.
Streaming has similar bitrates than what you get when you reduce a BD down to 2-3 Gig.
It still looks good for sure but if I would buy the disk I would not reduce it as strong as 2-3. Perhaps 10gb.
2.5 GB will give you terrible picture quality for a Bluray. Even streaming from Amazon or Netflix will be 5-6 GB for a two hour movie, and those are usually just passable.
Eh, I'm old, I can remember watching VHS and doing graphics at 320x256, my eyesight's not what it was, and I'm playing these things on a 7-year old laptop. That "terrible picture quality" does me fine.
I do set CQ a couple of stops higher for DVD, as per Handbrake recommendations, just because DVD has to get enlarged so much when watching fullscreen.