I went through my collection about 6 months ago and cut it in half by taking to my local used bookstore, called Half-Priced Books. They pay cash and I made about $70 on about 5 boxes of DVDs and about 7 boxes of old books.
Over the past couple years I've converted all my DVD's to Vudu 1080p or 4K and then trade them in at a used bookstore around the corner from my house. I went from having hundreds of DVD's to now less than 20 and only have those as they were never released on Vudu or don't have them in HDX on Vudu yet (The Abyss, Papillion. Victory with Sylvetser Stallone and Michael Caine). So I hold on to them till the convert
I was jettisoning content from my NAS like crazy and removing all of the local copies of movies I own streaming licenses for. While I was doing that, I discovered that Vudu had a bunch of them on sale for $7-10 each. It took a lot of self-restraint not to buy them. I'm trying to get rid of as much local media as I can over time, but I'm also trying to live on a budget, so...
Blu-Ray and UHD Blu-Ray are superior to their streaming equivalents and many condescending enthusiasts on other sites love to opine that philistines like me simply don't understand the importance of quality. The truth is that streaming has gotten so good, that I almost don't care about the difference and am willing to sacrifice it for reasons of both cost and convenience (though the former is less true as I transition to 4K).
While it is true that the average bitrate of a Vudu HDX movie is somewhere around 10 Mbps, they use a variable bitrate scheme that caps out at around 20 Mbps for those that have sufficient bandwidth. That minimizes banding and other artifacts to the point where I rarely notice the difference. Given that a lot of the UHD content now supports Atmos, the case for discs is even less compelling to me. The only real complaint I have about streaming is that it is inherently subject to network issues, but that is normally not an issue.