And science proofed that nobody can hear a difference in sound quality from 256kbit/s compressed files as long as they are created from the same / equally good source and in a high quality process like all the streaming services do.
Can't agree with you there. I can easily hear the difference between lossy streaming services and local flac files, volume matched. I even did a volume match test between streaming Tidal (lossless) and local hi-res flac files and I can pick our which is which. Even when the differences are small, they're still there, and when I'm spending thosands on a DAP and high-end IEMs to get the best possible quality, why skimp on the easiest and cheapest part to get right (quality lossless files)?
Depends. The R8 was perfectly able to drive my Hifiman Arya, a not so easy to drive planar magnetic. It needs 1W/32Ohms to shine and the R8 delivers. You would need something like a Heddphone or the like to be underpowered by the R8. So, it‘s quite comparable to desktop amps, even more powerful than many (like e.g. L30).
The R8 could easily drive my HD800 loud without breaking a sweat. That doesn't mean it can drive them anywhere as well as a desktop amp with significantly more headroom. Likewise with planars - they need LOTS of juice on tap, and the more you give them the better they sound. Don't get me wrong, the R8 is a very capable headphone driver, but if you want to max out the performance of your full-size headphones, chances are a high-end desktop amp will do it better.