

The main problem was that it interrupted the line. We’d have to stop and inspect each product, then reposition or replace the connectors, before the reflow oven. It also ran the risk of damaging the connector, the PCB, or even the inserter head if the insertion force was too high. We had a higher rework and scrap rate compared to similar SMD-only products, but using pin in paste meant that wave soldering could be skipped altogether, and I guess someone above my pay grade determined that it was better in terms of finances.
This is just my own experience. I don’t know Rpi manufacturing practices.
I’ve been using Arch (or some flavor of it) for several years, and I’ve never had any serious issues that I didn’t cause myself. The thing that might catch you with your pants down is if a dependency introduces a change that breaks another application, but catastrophic failures are fairly rare, as long as you’re willing to learn how to maintain your system.
Yes. The application is called Timeshift, and it’s specifically designed to back up the system files to a separate partition. If your root filesystem is btrfs, it can also manage filesystem-level snapshots that you can roll back if you bugger the system.