but if you want to disable colours in this why not use hexdump or xxd :D . it's like the only feature it adds to standard hexdump tools

I'm also not a fan of the colouring, especially in this application, because when you're looking at a hexdump chances are you don't care about ASCII or whitespace --- and it's not as if you couldn't tell whether something is in the ASCII range, given the character representation in the right column anyway.

The border lines don't help much either and seem more like decoration; addresses to the left and an indexing header on the top, like the traditional "canonical" hexdump format, would be far more useful.

How can you tell the difference between an unprintable character and whatever encodes them (I've most often seen '.'), in a single character cell, without color?

Me neither.

I did use it religiously for a long, long time; then tried without for a week and never went back.

It's not like telling the difference between string literals and keywords was ever a major issue for me. I guess it could help short term when learning a new language, but I'm pretty sure it slows down overall progress.

How does it slow down progress?

For me it doesn't. It's a quick way to see that I made a typo when a keyword doesn't turn the right color, or that I closed a strong with the wrong quote Mark.

I find it's a bit like navigating using GPS, once I get there I still have no clue because I was mostly acting on cues.

Slow compiles have the same effect for me, I get pushed out of flow and into reactive mode.

The only way to write good code is to be proactive, and any features that interfere with that process are worse than whatever "problems" they "solve".