I don't get why everyone's supporting the OP. It seems silly to limit your choices like this. Clearly credit/debit cards still bring a lot of convenience in this world. Why not take advantage of that?
Because banks and credit cards are also a huge pain, and the banking system will be quick to remind you about it if you do something they don't like.
Regarding boats, I see 2 problems with them.
The first is that unless you're in the Southern hemisphere, in Europe or Florida, you'll have to pay at any port to get in.
Then boats don't last as well as houses, and their maintenance can get really expensive.
I'll stick to land, but that doesn't mean to a fixed place. Freedom is in traveling.