Sorry if this is a stupid question, but if XCP are destroyed when being used for smart contracts and there are only 2.6 million. How will everyone be able to buy enough to run the contracts?
Like Matt said the XCP fees used in computation of smart contracts aren't constant values as they are in ethereum (like 1 XCP no matter what), but fractions of the total supply of XCP. Moreover XCP is divisible, So just as an example:
if there were only 1 XCP available a smart contract might cost 0.000001 XCP to run (and everyone would own fractions of a single XCP). Whereas if there were 1,000,000 XCP available a smart contract might cost 1 XCP to run. In both cases the amount of XCP in relation to the total supply, and roughly dollar worth of the XCP spent on running a contract could (and usually would be expected) to be the same, since In an efficient market you'd expect the opportunity cost of spending XCP to execute a smart contract would remain competitive. Nobody is going to spend $500 equivalent in XCP to run a smart contract that embeds a hash in the blockchain