You could always put NOPs into delay slots by default and replace them later with something more useful.

no, you could not "always" find something useful to put there later. gross exaggeration

You misunderstood parent. They meant you can always nop the branch delay, and you might find something more useful for it later

that may have been what they wanted to write. unfortunately they wrote something wrong and misleading instead. i understood what they wrote perfectly well and the implication therein isn't, somehow, my fault

The "always" qualifier does not apply to anything after the "and". Why do you assume it does? You are being very combative and pedantic so I assume you have a diehard rule for this that you can reference? Like some english grammar handbook?

Less so than register windows :)

From having read lots of disassembled MIPS code I can tell you that they become second nature very quickly.