This airdrop is limited for some years so no matter what the total supply will become stable so there is no need to sell for tron because you you don't know the fate of tron as well.
But I think it is good opportunity for people who own more trx to get more BTT but I do not encourage selling BTT for trx just for more because you do not know when BTT will get pumped. what if you sell and it gets bumped whilst trx gets dumped?