My reply is......
"I wouldn't choose it over dry and clean wood."
Wood with termites in it is more than likely rotten and moist. Therefore it will not burn well or be a good source of heat.
In addition, the wood has been outdoors long enough to attract the critters and if you are storing termite riddled wood near your house (and I assume you do keep your firewood within easy reach of your fireplace or woodstove) you are running the risk of introducing them to your house itself. Need I say more?