Microloading is a mediocre way to gain size and strength -- AT BEST.
We know what makes a good growth routine. Hardgainer doesn't resemble that. We know what makes a good strength routine. Hardgainer doesn't resemble that either.
I personally would rather focus on doing the best program for one or the other instead of focusing on something that isn't well tailored to either. Microloading just doesn't make physiological sense.
Casual I don't know if you've ever trained for strength/size but you sure as hell can't add 5 lbs weekly to a lift with any consistancy whatsoever. If you could your bench would gain 260 lbs a year. We all know this isn't happening.
There have been hundreds, if not thousands of trainees who thought they couldn't gain who have prospered from such a routine. For you to say it is a mediocre means for results is a purely theoretical statement, and not grounded in fact.
People in general make training incredibly complicated. They think they need perpetually compounded hyperbolic periodization to get big and strong. Casual you have your head on your shoulders in general when it comes to training, but saying that the weight increase is negligible to the body is completely false. You've been training for how long, 5+ years? Well if you added "only" 1-2 lbs to your lifts every week (and this is a PROVEN method), by now you could have numbers like:
350+ lb bench
500 lb squat
600 lb deadlift
So what are they now? And even though there is not an absolute correlation between strength and size, there is a STRONG one, and I'd be willing to bet you'd be a lot bigger right now. Success is all about focus and progression. That's been hardgainer's motto for the past decade.