Sometimes they put 5.1 sound on freesat only I think, I had some issues where I thought the BT box was not sending DD5.1. On closer inspection I found that it was only being broadcast on the sattelite channel.
2.0 is still surround sound it's pretty good too these days, I remember the original analogue decoder system on my VHS 🙂
pretty much any thing that appears to be stereo ( films, docs , drama etc) will have dolby surround encoded these days, that's the point of pro logic/ neo7.
it's a throw back to Stereo VCR's, NICAM tv's etc when they some how incorporated the 5.1DD from films into the stereo tracks to enable a monophonic surround channel.
It often sounds better on my set up than dd5.1 since I have no easy way to put my rear speakers behind me and true 5.1 can be a bit distracting/ OTT 😞
The main benefit really is for the Subwoofer channel IMHO (the .1 bit) but neo 7 does a good job here and how many people have subwoofers I wonder ?