Yeah, the "bioactive" craze is based less on facts than I'd like a husbandry methodology to be. One real problem is that it is a housing method that is supposedly appropriate for virtually every species of reptile and amphibian. That sort of lowest common denominator thinking is pretty much the opposite of good care (which I think needs to be based on the species, and also the specifics of a keeper's situation including their experience level).
Another problem is that the "bioactive" bandwagon is very market-driven; the folks selling the materials are making up the rules. 'Bio-Activity and the Theory of Wild Re-Creation', the book that literally introduced the term 'bioactive' in this context was written by the "Head of Innovation" at a herp supplies company. One way to sell more stuff is to create a market, and he did that phenomenally well. That company is also responsible for a poorly thought out and inaccurately marketed line of supplements.
Of the 11 references on the Wikipedia page for 'bioactive terrarium', seven link to vendors' sales sites (and four of those seven are specifically from dart frog sites, so not very relevant to any other taxa). Perhaps worth mentioning is that since I last checked the Wikipedia page, at least three references have been changed, and at that time only 6 of 11 were from vendors' sites (oddly, all the reference links to the Biodude's copy are gone).
The pages on "bioactive" at the Reptifiles website (which I am not at all recommending) are written by the owner of The Biodude, a seller of "bioactive" kits and material.