[cheebacheeba]

I have to disagree on the gimmickry point...and while some newer "old" DVDs can look decent on a new 4K tv.
They may look acceptable, they may even look "good" but a side by side would show there's an improvement in BluRay most of the time...even if it's just better fit to the parameters and display of the TV.

Then there's the even bigger case of the BluRay restorations like say "The Thing" - which I have never seen look so beautiful and "new" in my life.
Those ones are worth the upgrade.

Though for me?
I buy BluRay because the difference is negligible in terms of price, and they will just perform better and last longer.
Then there's a lot of cases where I'll have a DVD of #1, #2, #3, and I can upgrade them all onto BluRay and grab a set that will save a bunch of space...I mean that's what it's all about for me.
Keeping things running. Reducing space.
I already collect enough physical shit in my place, literally the walls are lined...entertainment is one thing I'd like to reduce in size.

Hell, make it all cloud/stream based and if the technology was up to scratch, I'd get rid of almost anything.

For me, it's not like they even have cool covers like VHS used to, I have zero connection to the aesthetics of most of these things.
Old shit just looks worse over time, and encounters compatability/resolution issues. That's why I do it.