This will NOT play 4K Blu-ray discs. Only regular Blu-rays. If you have a 4K TV, it will already upscale the 1080p signal to 4K as best it can. You don’t need this to do it. But if you need a decent Blu-ray player in general, this is an option.
So you’re saying (if I’m understanding correctly) if I’m currently using a (decent) BD player with my 4k TV, I likely won’t see any improvement with this item, because my TV is doing the work of upconverting to 4k from my current BD player signal?