Questions like these have come up here before, see: Dividend on COMP
As of today the answers I think are:
-
What is economic incentive for COMP holders not to sell it as fast as possible?
None as of right now besides a hope/assumption there will be an incentive added at a future date. -
What is economic incentive for COMP holders to make wise governance decisions
None as of right now besides a hope/assumption there will be an incentive added at a future date. -
Is there any kind of link between success of Compound token and price of COMP token?
None as of right now besides a hope/assumption there will be an incentive added at a future date.
The trading of COMP is purely speculative at the moment. Currently the only utility the COMP token has is voting rights.