iexec: is tokens on ropsten network cost some real money

Question

I am studying iexec for writing smart contract. I follow tutorial at this link. In this tutorial, at the last part, they say:

Be nice and give back your RLC and ETH to the faucet by sweeping your wallet:

iexec wallet sweep

This makes me feel confusing. Because as I know, iexec uses ropsten network and ropsten network only a testing network. So tokens are generated free for testing. So why in this turorial, they say:

Be nice and give back your RLC and ETH

Thanks

Answer 1

It's because it still a supplied currency, they may want to prevent mining or creating or missing some at a point!

Example: Ropsten network have a fixed limit of ethereum mined. The faucets usually request the developers to send back the ropsten so it's not lost and unused, since one day, it will be impossible to create new ropsten ethereum by mining. Same issue apply in your question.