4K Movies - Digital vs. Disc - which is better?

[VideoDave]

Hi ALL - not new to the forum but an infrequent poster, despite owning over 700 DVDs/BDs (70+% being blu-ray discs).

For the holidays, we replaced our 9 y/o LG 42" LED w/ a 49" Sony 4K LED (Sony XBR-49X950H) - fantastic picture w/ 4K streaming; do not own a 4K player - the Sony supposedly does some BD upscaling - now in our 70s, I do not plan to replace my BDs w/ 4K versions, if and when available (a lot of my films are older ones and unlikely will see UHD releases).

My question is whether buying a 4K streaming version of a film (vs. the physical 4K disc) would provide a similar viewing experience on this new Sony UDHTV? I suspect the physical disc would be better, but is there much of a difference? As an example, I did purchase two 4K films for streaming from Amazon (Dr. No & Sense and Sensibility) which I did not own, and both looked great to my eyes. Thanks for any comments. Dave