Indeed, your points are all valid, and if you are doing it just for "fun", yea, totally, auto's are just fine.
But I thought the intention of growing and harvesting marijuana is to take advantage of its medicinal purposes, no? Auto-flowers are part Ruderalis (sub)species, the thc and cbd cannabanoids that it produces are far less potent than that of sativa or indica. The only advantage Ruderalis provides is that it automatically transitions from vegetative to flower in a certain period of time, generally 3 weeks. So of the faster known auto strains go to flower in 2 weeks.
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If that's the only advantage, then why not just use regular seeds or feminized seeds and transition to flower in 2 weeks manually? In the end you will have the same sized plant, but the likelihood of a potent medicine is much greater. And you get a chance to experiment with a lot more variety.