The fact is, difference in the TPM comparison is so big because the source was quite poor - in comparison to BD, for sure, hence it looks… well, “better” - at least, watched at 1x; in motion “should” be even nices. I guess BD would look not so sharp, yet better than simple “go and upscale”. Color grading apart, of course.
I guess also TPM could have some value, until a 4K (or more) scan will be ready.