Spinning at high speed is bad for your cloth. It wil stress long every lining in your cloth. Specially those rubberband type. My WM have 1200rpm . But I have to slow it down to 1k or 800 rpm depend on the cloth. My cloth still can dry as usual under the sun.

For dryer can consider need or don't need. My situation is like this. I brought a WM for the purpose no need go laundry shop for all my cloth. So I need at least can wash comforter size and able to dry too. So wash and dryer is need. Second, when I have a busy week, there is no time for me to wash when I have to comeback night. Can't see the sun too. So I just I just throw my cloth into WM and set it to wash and dry. Morning I just takeout and wear or put in wardrobe.

Third, I don't need all the time in my home which I have to watch outdoor Incase rain when dry my cloth under the sun. I only have time wash my cloth weekend. That is also my weekend shopping, dating and clubbing.    if raining season situation, that is most handy for a dryer.

Dryer can save me some time and no need hard planning when you want to wash your cloth. But I hardly use too to avoid high bill.

Not really. But it is a minimun load for the comforter. Any less than this, the comforter can't stuck in.

You can't compare with normal washing machine. You are looking at combo type.