You don't "need" to touch these knobs. Think of these deeper controls as a bunch of free trips/servicings and mods from your local amp tech. The deeper settings can easily do things that we normally refer to as "Mods". Things that guys pay well over $100-$300 a pop to have your local tech do to your amp. If you don't know what it is, or what it does, if you don't understand the reason to do it, then it is like opening up your amp and working on the internals with no understanding. You will likely mess it up. Instead, look into the WIKI, educate yourself before you work on the inner workings of your amp. Luckily, you won't die messing around with an AXE-FX like you can messing around with your tube head. (Ooops... forgot to discharge a big capacitor) On the other hand, if you have an hour or two to burn one day. Back up your presets, and tweak away to your heart's content. Try that with a tube amp which can only allow you a couple knobs, or it's a trip to the tech, or serious DIY self education (dangerous territory for most common players).
The wiki and manual have a lot of great info on an amp by amp basis for some of this stuff. There are some cases where even the traditional B/M/T/P is a superset of the controls on some of those simple vintage amps. In those cases it is really helpful to know how things are mapped. Alternatively, there are a few amps where specific switches on the amp faceplate are mapped to or are equivalent to a differently named AF setting or value. If you really want to deep dive a specific amp, its worth looking up the wiki entry on it.
