Your Bitcoin income from signature campaign or other bitcoin related services should be channeled into Bitcoin economy
What a better way to spend your bitcoin income than using it to pay for goods and services in Bitcoin economy.
It depends on what you want or need and the availability of the marketplace in your location; I can only pay part of my income from the signature campaign on domain registration, hosting, and VPN, but for my basic needs I still need to trade it for fiat.
There is no marketplace in our area where we can directly spend Bitcoin on what we want and need. I wish we had a marketplace that offers the option to pay with Bitcoin, so I don't have to trade my Bitcoin and do it directly.