the psycho-active ingredient is the same. they can produce viable offspring, so they are very much the same plant. The trigger for flower is different. Ruderalis tends to be less potent, though those differences are mostly minimized by now through selective breeding.
an autoflower is good outside to avoid a wet season or a cold season. I don't know how, but if providing a dark cycle is somehow impossible, it'd be good for that context too, but seems more lazy than necessary, lol.
autoflowers are not faster. They don't magically circumvent the same growth needs/limitations of a photoperiod.
Anything an autoflower does (except randomly flip to flower), a photoperiod can do just as well. You can run a photoperiod 12/12 from seed and get the same range of weeks until completion.
i'm sure yield can be similar... but the greater inconsistency of autoflower size from varying vege phase length makes maintaining a consistent canopy more difficult, which will impact consistency of yields, too. (in addition to the shared and similar, likely the same, variable nature of bloom length)
in the end it won't matter much to anyone that keeps a plant healthy... if not as confident about such things, stick to photoperiods as you have more leeway to fix mistakes in vege phase.