Services like BitPay require transactions to go through quickly. If your transaction arrives an hour too late the bitcoin price in usd has changed and bitpay refunds you your money or asks you to send more money. In both cases you have to pay the transaction fee again.

I wouldn't be surprised if a high transaction fee increases the speed of deflation. Smaller transactions are stuck and will be forgotten. Spending the currency is difficult. All you can do is hold or convert to fiat.