Is banning ahrefs still worth the effort?

depends what you're trying to hide. blocking AhrefsBot stops it crawling your site, so people using the tool can't see your pages or the links going out from them. it does nothing about your backlinks though - those get found by crawling the sites that link to you, not yours. that's why it's mostly PBN owners who bother. for a normal site it doesn't buy you much.