Yes some generators are noisy, mine included.
That's why most campgrounds have
specific "quiet time" when you aren't allowed to run them.
Generators and inverters are 2 different pieces of RV equipment that do 2 fairly
different things (that just happen to go together).
In my 2002 Roadtrek, they work like this.....
Generators turn gasoline (or some use propane) into electricity by a (noisy) mechanical process
and use an inverter (built in or separate) to make it usable as 110-120VAC power like
you'd have in your home wall outlets. They often also recharge your "house" or "coach" batteries
at the same time. My van has a couple of regular 2/3 prong plug style wall outlets to run electric "stuff"
while my generator is running, or when I'm plugged into "shore power" with the big black cord
which is located on the outside of my van. Laptops, TVs, chargers, cell phones or anything else
which needs AC current can run off them then.
I also have a few "cigarette lighter" type sockets located in the entertainment unit at the rear of my van
that are attached to my coach batteries. They can run "stuff" that has a plug that fits like a cigarette
lighter and only needs 12VDC power. I have a small dirt sucker vacuum cleaner that runs off 12VDC
power, and has a "bullet" shaped plug. It plugs straight into one of the 12VDC sockets and I can clean
up those little spills and messes off my coach battery power.
Inverters merely change the format of the electricity from 12VDC (like your vehicle or house/coach batteries)
into 110-120VAC power (like household current) for anything that needs AC power.
So, if you have a 12VDC to 110-120VAC inverter in your RV that can be connected to, and draws power
from your house/coach batteries, you can run your appliances that need AC current off those outlets
for as long as your batteries have power in them. When the coach batteries are drained, you'll need to
run your van's engine or your generator to recharge the batteries, so the inverter can again turn the DC
battery power into AC current to run your appliances. I have 2 small inverters (purchased at Canadian Tire)
that provide low wattage (less than 100W and 150W) AC power when plugged into the 12VDC power
sockets in my e-unit. I can then run my electric "stuff" that needs AC power off of the coach batteries,
which are actually stored DC power.
So I don't have to run my generator in that case, to use my low draw AC devices. (Until the batteries are drained)
Or, if you're in a proper campground with 30 amp power at your campsite, you might plug into shore power
which is also AC current to run your electric "stuff". It also often recharges your house/coach batteries while
you're plugged in.
So it pretty much depends on how much AC power you need for what you want to run, whether you'll need to run your generator to power whatever it is, or whether you can use an inverter to change the 12VDC coach/house battery power
into 110-120VAC power for short periods of time, before you have to then run your vehicle engine or your generator
to recharge your coach/house batteries.
Simple enough, eh?