3DPrinting

The PCB doesn't do anything other than a compacted connector between components. Especially the surface mount component. Also, some devices can be more sensitive than others making it more prone to breaking during mishandling. If something on the pcb breaks (highly unlikely), then you can just solder using jumper wire (to some degree, high speed signals cannot be treated this way). However, if the component on the PCB is the one that breaks, then you can just replace that component with some careful solder works. But yes, sometimes replacing it will be easier than repairing

I use a version of Hartk's Stealthburner PCB on my voron and cludged an afterburner tool head onto my franken mk3s. They're both breakout PCBs, the stealthburner one to my knowledge is passthrough, afterburner one has a thermistor and led on it for chamber temps and a hotend activity led. Totally optional and what you've done already is probably the more frequent things I'd change anyhow. There are fancier tool head boards, they're effectively their own MCUs afaik that communicate via canbus, with those ones you're running very few wires, something I'm thinking about but haven't done yet

For me, they reduced the amount of wiring I needed to run to the hotend and make it super easy to swap components, as I said, I've damaged things unintentionally before (I'll say ADHD is contributing to that) so it's really handy. Keeps the wiring neater as well, or at least gives you a place to manage them.