Freicoin (like bitcoin) would eventually reach a user base equilibrium and have an increasing value based only based on growth.
But if the deflation rate is lower than the demurrage rate you still have an incentive to spend or lend your money.
Sorry, I was specifically asking why people would start. When Bitcoin was worth $0.001 penny, you could buy thousands of it, hold onto it, and watch it eventually become $0.01, then $1, then $10. Why would people buy $0.001 freicoins if they know that thanks to demurage it'll be worth $0.000 in a short while?