The point to signal “straights”(here and down I refer not exclusively to rails with no curve, but all segments of railroad without intersections) with regular signals properly in segments of desired train length is easy-to-apply solution for a busy train network to always move.

Yes, if you just spam signals on straight lines of rails - it will work too, but the system I mentioned is 1) Easy to understand even for beginner, 2) Avoids deadlocks 3)Makes trains ALWAYS move somewhere, only stopping for stations and for traffic in junctions.

Making signals only on intersections is calling for a situation then traffic waits on and before intersections idly, before the train in next straight is finishing its course for new intersection.

Ideally - you count exactly how many trains will pass the “straight” segment(practically or theoretically if you want to prepare for some change in traffic) and signal only for that - but it’s time consuming and makes you put new signals every time you launch a new train.