I have a really slim wallet, which is only possible because I never have to use cash. Also cash is dirty. I can wash my phone once a week to keep it clean but I can't do that with cash (well I can but what's the point, and I'll get accused of money laundering /j). It's inefficient since you have to count your coins and bills and the cashier needs to do the same and then you have to check if you got the right change. You can also misplace cash, especially coins.

Meanwhile I haven't had to handle cash for like 6 years now except for extremely rare circumstances and it just feels way better.