E.g. continuously stirring the pasta while you could be doing something is a waste of time where you could be doing something else, so less "efficient".
Turning off the heating and letting the water cook covered uses very little energy but takes more real time so also less "efficient" in a way.
More active stirring also tends to break up the pasta, so depending on what kind you use you may end up with a different outcome (works great for pasta e ceci or pasta e fagioli! Wouldn't want it for spaghettini)
Mostly, I think the traditional way seems unnecessary because modern pasta is a lot stronger than it used to be. I you try to make a one pot pasta with low quality pasta (low protein) you may end up with glue (source: am Italian, live in country which produces shitty pasta).
Yeah, lot of cooking is up to personal preference. In my case efficient here means using less water/energy. Optionally it can also be using less time, but that depends on what the end result is supposed to be.
As for the stirring, I'd say "it depends". Personally, I prefer to use fresh egg pasta. It cooks in maybe 2-3min and does require maybe 1min of stirring (maybe 20-30s in the beginning and end and perhaps one or two quick checks in between). I'm fairly sure I'd stir it somewhat of I used more water and I'd definitely need to strain it, so there the amount of time / effort is at worst the same, at best slightly in favor of using "risotto" method.
When it comes to dry pasta, I guess it depends on volume. If You're cooking a batch for 10, the traditional method probably makes sense. Otherwise, I pay attention anyway to how much the pasta sticks and clumps together.
E.g. continuously stirring the pasta while you could be doing something is a waste of time where you could be doing something else, so less "efficient". Turning off the heating and letting the water cook covered uses very little energy but takes more real time so also less "efficient" in a way.
More active stirring also tends to break up the pasta, so depending on what kind you use you may end up with a different outcome (works great for pasta e ceci or pasta e fagioli! Wouldn't want it for spaghettini)
Mostly, I think the traditional way seems unnecessary because modern pasta is a lot stronger than it used to be. I you try to make a one pot pasta with low quality pasta (low protein) you may end up with glue (source: am Italian, live in country which produces shitty pasta).