Don’t know what part of the country you’re in, but in Chicago even the basic chain grocery stores carry fresh unprocessed turmeric now.

There’s basically no reason to ever use powdered or dried.

Except that it's a different ingredient, that tastes different and works differently. I still use cayenne for some things even though I have fresh chile peppers I don't put fresh ginger in ginger snaps etc.

Diaspora also lab tests theirs, plus the variety they sell has a high curcumin level

isn't arsenic in rice trivial to deal with ("pasta" method)?

I wouldn’t call it trivial, no. Pre-boiling it only removes about 50% of the arsenic. If you start with US rice from arsenic-poisoned soils, after boiling the rice you can still have more arsenic in it than rice that had lower levels to start with (even when cooked traditionally).

One needs both to soak rice for at least 8 hours and boil it in excessive water to remove arsenic.