I really agree with all the pruposes.
I host more than I travel, because my kids are going to school, so we can only travel a few weeks during school holidays, but we all enjoy hosting nice people, so they can discover life in France, the place we live, and in return, travellers talk about their country, cook sometimes food we have never eaten before, teach us some words in their language...
When people are staying longer at home, they help in return in the house, or playing with the kids...
Free travelling is not only get a free bed, we are not hostels, but it's really an exchange.