I mean, there are some legitimate reasons.
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Non-rechargeable alkalines do have very low self-discharge rate, so they work well if you're gonna stash a flashlight somewhere for a long time for emergencies.
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The voltage on different types of batteries is not the same, and there are some devices with power supplies that cannot handle a wide-enough voltage range. I have a Grundig G6 shortwave radio, for example, which will not run on NiMH AA batteries (1.2V, rather than 1.5V alkalines or lithium). I suppose that I could get rechargeable lithium-ions, but I don't really want to deal with rechargeables with different battery chemistry floating around, and my current battery charger can't handle lithiums.
I just remember the 1980s, where the norm was alkaline, and people had to buy the things all the time for all kinds of battery-powered devices. Was nice to be able to just recharge batteries at home.