I think I fully get the main point you are driving at. Imagine paying for a cup of coffee in a coffee shop and you have to wait for at least 10 minutes before you can go out because the payment has not yet been confirmed - in this scenario it could really be a big hassle. However, it might be a little different if we are paying online - that 10 minutes wait can be tolerable that is assuming that you are doing things online at home maybe. Now, I also understand that we already have Lightning Network that we can use and being utilized by merchants who are accepting Bitcoin. There will always be solutions to different problems as long as there can be a demand for it - or there can be money that can be made.