It won’t change at all. If anything the price will go down.
Why? Because those who are buying the tokens to sell for gold will be absolutely unimpacted by this restriction. While the bots who may be buying them could have issues.
The result is the same amount of WoW Tokens that need to be sold but less buyers… Assuming all those buyers don’t just go buy one of those 60-day time cards preemptively.
Botters (the main people impacted by this change) will no longer be able to buy tokens on their new throw away accounts. This will mean a drop in the demand (and price) for tokens, but people are always going to buy/sell gold. Tokens are never going to die on an active realm.