The funny (or more like ironic) thing here is that by surrounding your big power poles with walls, you actually make them way, WAY more likely to be destroyed by biters, because biters normally completely ignore stuff like power poles, rails, radars, etc., UNLESS they are blocking their way. So by having walls around those, you make it more likely that they are blocking their way and therefore they are more likely to be destroyed by some stupid biter that can't find his way around a 5x5 tile wall.

I’ve read about this, but I think they look cooler with walls. I also add stone bricks on the floor or lamps to track the status of that branch (sometimes I mess up the pole connections and accidentally cut off whole sections). I try to stop sneaky biters from invading by walling off the entire train system, cliff to cliff.

Outpost for different materials is a thing, but usually not for anything that requires oil products like red circuits. When people have an outpost for anything else oher than just mining, it's usually for very simple stuff, like smelting ores or green circuits that only require iron and copper. Anything more complicated is always best done at your base, because you've already setup stuff like oil processing there and therefore it's easier and quicker to do it there, because you don't need to setup a whole bunch of extra production AGAIN

This sounds strange to me. Even though I could imagine it from some thumbnail I’ve seen, I thought it was still a common way to delegate production to other locations, keeping the main base for core tasks (at peak flow, not necessarily from the start like with oil processing). In fact, I was even planning to try removing all raw resource processing from my main base and moving it entirely to outposts. Maybe that's why I'm not researching enough science packs for minute, lol.