My dad still uses the family (his dad's) rice cooker from the mid 1950s, so they aren't that complicated, they're basically a heater and thermal cutoff
PSA for anyone who doesn't: Wash your fucking rice
Even better: use no-wash rice. It's easier for you, and better for the environment:
> [...] believe it or not, the cloudy water consumers pour off when washing their rice has been identified as a significant source of water pollution in Japan. In the B.G. method [used to make no-wash rice], the bran comes out dry, so instead of going out with the wash water and ending up in rivers and streams, it can be diverted into fertilizer and animal feed.
and:
> It’s considered enough of a problem that the Tokyo Metropolitan Government urges residents to water plants with their togijiru [cloudy rice water] rather than sending it down the sewer. And Shiga Prefecture, in an effort to protect Lake Biwa, has asked its citizens to switch to no-wash rice.
What? Sure, if you want to remove some of the starch, but what if you don't? I don't really know why you should if you don't want to, unless it was dirty, but rice today comes pretty clean of debris and bugs. Plus, it's going to be cooked, so no problem there.
It's not for safety: it's because starchy rice sticks together and makes clumpy bad-tasting rice, it's also much more easily seasoned in my experience if you wash it first.
PSA for anyone who doesn't: Wash your fucking rice