This article argues that clever pricing strategies and the ability to cut transaction fees payments less than $1 may help speed the adoption of cryptocurrencies.
https://cryptostar.money/blog/britain-is-keeping-the-penny-lessons-for-crypto-marketing-teams/--- update 15:33 ---
Great points Beerwizard and Stompix below.
When using crypto the buyer pays the transaction fee. Cash is cheaper for them unless they get a discount.
Merchants using Lightning Network might have to close their channel each night to keep their books in order.
Why would people bother using Bitcoin if they would also be charge with fee on each transaction?
Not to mention that there is also a tax on the receipt from the merchant .
So I guess people wouldn't really use Bitcoin as a currency to pay for anything unless the cost for transaction fee would be zero.