Electronic – find DMM probe sockets

Sharp tips are able to poke through insulation, whether it be wire insulation, or the coatings on circuit boards. They are also handy if you need to stick it down into a connector between the wire and the body of the connector. Also, as parts get smaller, you need sharp tips to be able to contact one pin of an I.C. without shorting to the others. Lastly, a sharp point isn't as likely to slip when you look away to read the meter. The flow of current from a point isn't meaningful here because that's only relevant when there's an air gap present.

The response time of the continuity "beep" is important. If you want to test a number of contacts--especially if you're hunting for that one signal in a large set--you want to be able to do it fast. Otherwise, you have to touch the wire, then wait, then move on. It's very unsettling when doing continuity checks to have to rely on the notion that "it didn't beep, therefore there's no continuity". Did I wait long enough? Did I actually contact the wire? This is why you start by touching the meter leads together to be sure the beeper is actually working.

No, there really isn't any significant simplification possible. When you interface to the power line, you have to make your design as robust and fail-safe as possible, in order to avoid product liability issues.

Even if the design of the wall socket permits only one physical orientation, there are enough mis-wired wall sockets out there that you really need to treat both Line and Neutral as "hot" inside your product.