I think you keep missing my point. This isn't about a "usual web form". You aren't entering your address or something. You're configuring a service or server. Those are very different worlds. I understand that those kinds of forms where you enter your address (or whatever) wouldn't ever have a default in there. In that context a default doesn't make any sense (default name, default street, default city?). And even in the cases where it might, it would be - as you pointed out - unexpected for the kinds of users that usually fill out "web forms".

When you're configuring a server/service, that's a very different world. Many fields could have defaults, and you wouldn't want to hard-code those into your config. That is what this is. It's essentially a web interface for a config file, which often has default values for any field you don't specify for a variety of reasons. Defaults DO have special meaning here. That's the whole point I'm trying to make! In that world it very much makes sense. The best way to show it is obviously a matter of personal taste, I actually like (and prefer) the greyed out way for reason I mentioned above.