[timr]

You're not going far enough: before Covid, finding a place (excluding conbini) that took a credit card was rare. Credit cards are common now, like you say, but nearly any business will still accept cash.

I think I've encountered at most 1-2 restaurants in Japan that don't take cash, and none that don't at least accept credit cards.

[steveBK123]

Yes as recently as 2010s Japanese travel as a westerner was mildly stressful managing your cash balance.

Taxis, conbinis and restaurants all wanted cash.

Lots of ATMs (majority even) don't take western ATM cards, so you need to look out for JP/7-11/Citi? ones.

Delicate balance of keeping enough yen so you don't run out / have to go out of your way ATM hunting but also not head home with $100s in yen you don't need.