I am not going to speak for others but I have bought a lot of Paizo’s 2e humble bundles and I would not have otherwise bought any of their 2e books at their individual listed prices.
I have never played in a Pathfinder 2e game and I don't expect to run one, these are all just extra non essential lore books for me as I use some aspects of older Golarion in my 5e homebrew setting and I have plenty of setting material from the 3.5 and PF 1e Paizo eras.
I just am not going to spend $30 on the Tian Xia setting PDF. I have a mild interest in the setting and some Asian fantasy stuff in general but I already have the earlier Pathfinder 1e short sourcebook on the area which I have not really gone through and have not incorporated into my homebrew setting. I also already have a bunch of other fantasy Asian stuff from Kara Tur to Rokugon to Mists of Akuma and others.
But I did spend $30 on the bundle with that big PF2e Tian Xia setting sourcebook, their giant character options book fleshing out the new races for the setting and such, the associated Adventure Path, the new Monster Core with things like their new core dragons and outsiders, a bunch of short pathfinder society adventures, a bunch of flip mat PDFs, and so on even though the first bunch of PF2e core big book items in the bundle are duplicates from previous ones I bought. The 20 or so new things were worth it at the $30 bundle price for me.