This is really interesting regarding the extra water and I suppose it makes sense with the more basic models that have a vent hole. I have been using an Instant Pot for a bunch of years now and have a custom pressure cooking setting that gives me fluffy and perfect brown rice using water at a 1:1 ratio. I believe the cook time must be slightly longer than the white rice setting(default button). 21 mins and about 10 mins to cooldown before venting gets perfect results 100% of the time.
I have been tempted to invest in a more traditional cooker like a Zojirushi thanks in large part to “Uncle Roger” but paid $45 for the Instant Pot and I don’t really use it for anything else.




You bring up another important positive for the instant pot: when I wash the rice, I tend to scrub hand-fulls between my fingers under running water and swirl it around as the bowl fills. Since the inner pot is stainless steel, I am not worried about damaging a non-stick coating like you tend to see on other rice cookers. Additionally, once the cooking cycle is complete, I have learned that letting the pressure drop over a period of about 10 mins before venting helps release the rice from the bottom of the inner bowl so sticking isn’t really a problem and I never get any burnt rice either.
The one thing I am not sure about is how well the rice would keep if it is left on warm all day like you describe for households that make a large batch for multiple meals. I typically make just enough for the meal at hand and some leftovers for fried rice later so I suppose the instant pot serves it purpose well but it may not be the solution for everyone.