I collect HP calculators: I have an HP 12C, an HP 15C Collector's Edition (there are a few of them left still for sale), an HP 32Sii, and an HP 48SX. I sometimes use them, but whenever I'm in front of a computer (which is almost all the time), I find myself using the Unix dc command.

Handheld calculators are nice, but outside of exam settings, I could use a smartphone or a computer, though calculators are nice when I want to work distraction-free through something that requires performing calculations. I believe this is why HP largely exited the calculator market: HP's target market was professionals, and cheap computers and smartphones killed the calculator market for them, similar to how electronic calculators killed the slide rule. Texas Instruments, however, is still in the calculator business, largely due to their successful courting of American middle and high schools, as well as ETS and other testing agencies, beginning in the 1990s. I don't know the situation in Japan regarding calculator usage, but I see Casio scientific and graphing calculators proudly displayed at electronics stores such as Yodobashi Camera and Bic Camera.