I completely agree with this. From the community’s pov, it’s absolutely useful to know these things to determine public policy. If only gummints WOULD use this info to determine public policy and not just ignore it! 
But you lost me here:
I don’t think there are “all kinds of reasons,” although I guess, curiosity is a legitimate reason.
I’m in agreement with @Slash1972 and @SayTwo . From an individual pov, testing makes LESS sense than it does from a public policy pov. (I’m not saying it makes “NO sense.”) A positive test gives you useful information re exposing yourself to other people, whether you’re at work or at home. But to me, you should ACT AS IF you’re positive when deciding what precautions to take no matter what the test says. IOW, take ALL precautions, regardless. (Kind of like if you reellyreellyreelly don’t want to get pregnant, then use protection EVERY TIME, even if you think you can’t or can’t “this time.” Guess what? You CAN this time.)
My concern is that negative test results can lull people into a sense of false security and cause them to relax procedures. A negative test doesn’t tell you much, except that you don’t have it right this minute. It doesn’t, by any stretch of the imagination, tell you that you’re home free. You could be pre-symptomatic. This is one of those times when odds and risk levels taken at the individual level are not a good decision-making tool, as the consequences of a miscalculation could be deadly for you or someone else. They could be deadly for someone you’ve never even met… or for someone in your own household.
The best, safest strategy is for everyone to act as though they have it and as though everyone they come in contact with has it. Because they might- on both scores. That means wearing a mask and only being around people who wear masks. Distancing, hand-washing, etc. Within a household or a bubble this is definitely problematic and you will have to make tough decisions. Even Deborah Birx came out the other day and said if you live in a household with someone who is especially vulnerable, you should wear a mask around them at home (and they should, too, as the best protection happens when BOTH parties are masked).
This is serious shit. Playing the odds is not smart. Yes, there are people who cannot isolate, who have to work, who live with others-- obviously a total lockdown is not possible for them. But to the extent that it is possible, each person needs to do everything possible to reduce their chances of (and yeah, that is probability talk, so sue me for being two-faced) getting or spreading it as close to ZERO as they can.
But IMHO people aren’t scared enough. Just being lonely, wanting to go bowling, or attend a big wedding (no one should be having big weddings, FFS!), missing your night at the pub or bar, wanting to spend Labor Day weekend at the beach just because you’re tired of CV-19-- not good reasons to relax precautions. FUCK-- we’re all tired of this MF… and some are dead or mourning their dead, and that’s much worse and more permanent than just being bored.