That got me curious. The drink that English speakers often refer to simply as "chai" is the Indian drink masala chai, meaning mixed-spice tea. Chai comes to Hindi through the Cantonese "cha" for tea.
Why not your personal identification PIN number? Gotta be specific. Your personal PIN number is just the one you like, but it identifies nothing. Same with the identification PIN number. It identifies something but not sure what. And a personal identification PIN, well, it identifies someone, and uses a number somewhere.
Oh man, I want to use a longer pin for my card so badly.
From what I understand, the banks mostly support it, the problem is that not all point of sale does. Those terminals are frequently cobbled together with some pretty garbage software and if it's hard-coded to four digits, whelp, good luck. I hope tap is working.... Or NFC or something because otherwise, you're SOL.