There is no reason not to add a highly liquid asset such as Bitcoin for payments. For big payments, transaction speed does not matter and therefore nobody can use the block time as an excuse. For small payments they should offer payments in the Lightning Network. It works wonderfully.
Agree with you; for big companies and big payments, delay time or transaction fees don't matter. But for small payments like paying bills for coffee shops, it's hard nowadays since most of us aren't familiar with the Lightning Network yet. Even for me, it looks quite complicated using the Lightning Network. But it's good to see even big exchanges like Binance have been adapting the Lightning Network by enabling withdrawals on the Lightning Network. Hope day by day Bitcoin users will start using the Lightning Network.
Bitcoin is slow, volatile, and expensive for buying coffee. Its real revolution isn't replacing your Visa card—it's replacing the foundation of the system Visa sits on.
Regarding slow Satofan44 already answered; it just depends on our good intentions. Also merchants need to add the Lightning Network to solve the issues regarding slow payments and high fees. I don't think Bitcoin could replace the traditional payment system, but Bitcoin will be another option of the payment system.