I'd say, one could argue if it's obvious or not for filters to not appear on product pages. i can think of many other modules on listing pages that are making even less sense on product pages. All of which AMM can deal with.
I'd also say, considering that AMM was € 50 until a few weeks ago, what else it does for you, and that it's for a truly "unlimited" license, € 25 is a steal.
Why not pay extra for a good, well supported product providing extra functionality? You and I have done so with HikaShop Business, and at least I have happily done so with NoNumber for AMM and other extensions as well.