Hugely disagree. Config files will modified by non-experts of the application 1000x as often as the actual developer of the application. Those people won't and often can't go look at the code.

Also, it can be really hard to find where exactly a configuration value is used. You may have to trace through a ton of code to find the place, and then you can't be sure that's the only place it's used.

Configuration comments are crucial, both for onboarding new users (explaining what the default is if you don't set a value, explaining what the configuration value actually controls, etc) and for experienced users to tell others why this esoteric configuration is set the way it is.

A configuration file is literally just a stack of magic numbers and strings. Why are we setting threadpool to 10 and not 1000? Why are we disabling X feature? What the heck does TPS_Report=true do?

You need comments.