$CVX is essentially a levered ‘wrapper’ for $CRV (Curve finance). The Curve voting power that Convex accumulates is directly passed on to $CVX holders who lock their tokens, known as vlCVX (vote locked CVX). 

Demand for $CVX mainly comes from the demand for the underlying $CRV & market demand due to yield provided by protocol bribes. As long as Curve maintains market demand and has a stable swap liquidity moat then $CVX should also reflect this demand.

Convex creates value by providing a yield optimisation service for Curve LPs/CRV holders & by also allowing protocols to direct liquidity to their products in a more efficient way.

Convex takes a 16% fee in exchange for its yield optimisation service, which is subsequently paid to stakers. $CVX holders also get bribes from protocols wanting to use the underlying veCRV voting power. Meaning that these bribes are a form of yield for holders. Token demand will reflect this somewhat, thus reflecting value of asset.

Convex takes a 17% fee cut from their Curve and Frax optimisation solutions. There is no treasury allocation for these fees, they simply go to CVX and derivatives (cvxCRV & cvxFXS) stakers.