I think the mostly-accepted opinion against taking cuttings from autoflowering strains is... somewhat incomplete (note that I did not state "incorrect"). I accidentally "crunched" a White Widow Auto - just after it had started flowering in earnest - down to the first set of true leaves. The... err... repair didn't take, so I tossed it. I was talked into retrieving it from the trash can and seeing if it'd recover in any way. It went on to do fine.
"Fine," in that case, was less than a half-ounce. But it was in a two-liter bottle of soil and not exactly in a "hardcore garden," so I wouldn't have expected more. Unfortunately, this meant that I cannot say whether or not the plant would have performed "fine" in a larger container such as a three- or five-gallon bucket, more light, actual pH monitoring/adjustment, et cetera. I mean... I'm sure it would have yielded more under those conditions - but I have no idea as to whether it would have been comparable to one that had been grown under them and allowed to retain the top 90%+ of itself.
As to the worth of taking/rooting/growing cuttings from an auto... My guess is that, yes, there's a whiff of "diminishing returns" about the whole thing. But, like most other things, it's probably... "situational?" I'm not feeling especially intelligent at the moment, please forgive my inability to use a more apt word. If you've got space aplenty for your plant(s), then you might not mind if they cover a relatively large area... this could be a thing that is actively encouraged. But if someone is growing in small containers with a dense planting, then they are likely to see branching and such as a negative. They might trim the "excess." At that point, they've got cuttings. IF they also have some space here and there - perhaps in the corners or wherever - then they don't have a great deal to lose by rooting the cuttings and sticking them in those spaces. Say they do this with four cuttings, one for each corner. Not the most well-lit part of their grow space, the four clones are behind the curve in development, et cetera. The four of them only end up producing an average of 3½ grams each.
What a miserable yield, yeah? Yeah. Yeah... But they each produced what, in some areas, might cost $50. An extra half-ounce (in total) of bud - for what, ultimately, wasn't likely to have been much extra cost in materials or labor, probably no extra electricity... and low expectation - because they went into an existing grow, and as "filler."
That's not a recommendation to go buy clones of someone's autoflowering plant, LMAO. It's just... If you have the materials, the space, et cetera AND you don't expect miracles... I don't really see any significant downside.
You might be wondering, "Why not just plant four more autos?" <SHRUGS> IDK. Remember, in the scenario I described, the rooted cuttings didn't go into "prime real estate." They were, more or less, an afterthought. They could even be said to be expendable; worried that applying "x" to your plants might kill them deader than last Christmas? Those hypothetical cloned autos have just volunteered to be cannon fodder, lol. If you try something on them and they die from it, you can safely laugh - because not only did you learn something, you did so at no cost to your "main" plants.
I am, of course, just jabbering. But there's a thread here somewhere in which the poster revegged an autoflowering plant. Successfully.
I would suggest, for anyone interested in playing with the concept of taking cuttings from autos, that they do so as early as possible, preferably before major flowering occurs. But after seeing the reveg experiment, I don't even know if that's a requirement.
I've always been a fan of sticking 'em in a five gallon bucket, hanging a mini sun over them and waiting 3 months. 
My goal almost always is to grow the largest plant/harvest possible and that seems to work. 
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