Sorry, DS was sitting on my lap and must have pressed ALT GR
I can try to answer a few questions as I did a lot of research into it before DS was born and after.
Lots of laundry - probably about as much as using cloth nappies, maybe slightly more (although that would mean you had a full wash load more quickly so maybe not a bad thing)
At night - some people use nappies at night. Others keep a bowl or potty by the bed and "potty" the baby whenever they wake at night. Newborns don't tend to roll around so it's quite easy to position a cloth or towel or nappy between their legs or underneath them - if you are co-sleeping it would be easy to adjust if the baby moved anyway. Apparently even tiny babies do tend to stir or wake slightly to wee and you become aware of this.
Hot countries - yes this is common in many countries, even China which is more developed than other countries where it is practised.
Going out - most people use nappies as back up when going out. I am sure they would not be very welcome guests if they did not! It would not be very comfortable for a baby to be in a car seat with nothing on so people do tend to at least dress them in tiny pants or training pants if not using nappies, under clothes. I think that being in a pushchair would mean the baby was too "removed" from the parent to notice cues so nappies would be essential or if they used slings all the time they might be able to notice in time to "potty" them.
You can do it part time and have the baby in nappies the rest of the time, apparently. I am not sure how this works as I thought it might be confusing but apparently it does.
As for benefits of it - well it's personal choice whether the hard work is worth it, but there are lots - money saved on nappies, less nappy rash, toilet training generally completed earlier (though this is not the aim), increased communication between you and the baby, baby not sitting in its own excrement even for a minute.
HTH (Also I got distraced while typing so apologies if thread has moved on)