Yes eating onsite including tips , shopping in the parks and resorts all can be charged back to your room.
Aside from tipping bell services for humping my luggage and buying bubble machines on Main Street I didn't touch my cash at all when staying onsite. Everything went on the Magic Band.

I usually only take $100-$200 and usually come back with almost all of it. So you really don’t need much and can put it all in a credit card either directly or via room charge tips and all

Yes totally.
U dont have to tip 20% btw.
We had awful awful service in 1 place and i left a 1c tip (so she knew i had to tip but she was so crap i didnt and we left a 40% tip as staff were beyond amazing (fyi at 50sptc)

Tipping is subjective.

But normally 15 to 25 per cent x

I always stay onsite, just charge everything to magic band which charges to my credit card, trip I've just got back from I had less than $20 in cash and it's usually the same for every trip, even non WDW ones

I use the cc for as much as possible including tips so I only take around $500 in cash. You also get the benefit of the business rate of exchange and that tends to be a couple of cents more than the travel rate.

We use CC for everything. $100 cash does us three or more trips. We have done a trip without spending a single cent of cash.

I find it amazing that people don’t take a bit of cash even for tipping. I always carry some cash for small purchases and even for emergencies ie lost credit cards.

Do a search on the new room charge/cc policy before making a decision, as usual they have managed to mess up something that should be so simple!
SD:d: