Even if all you are doing is contributing to data-collection for the epidemiologists, to enhance their understanding of the disease outside of acute illness, its worth it. A really back handed way to get public health funding to the forefront like it should be.

Antibodies are no guarantee against contracting it again.

I would do it if I thought I had had the virus. It may not give you immunity from some of the mutations but it might help them discover an effective treatment or vaccine if you have antibodies.

Just remember that at this point the tests may not be viable. False positives and false negatives will be rampant until it is found if the tests work as advertised.

Go for it! I think a lot of people had it before it was fully understood and with only mild symptoms. Since, thanks to the Orange Buffoon, there was not testing to speak of, the antibody test is the only way you will know for sure. But they have yet to decide for sure if having had it makes you less prone to getting it again, so stay safe.

We are doing that