Here's how I see it (and Im a new member, so save the rotten tomatoes until after I get off my soap box).
This is a specialized set of customers, if you are selling something. You want to sell on armslist to gun guys? you pay for it. You want to sell on gunbroker? you pay for it.
If you're selling some one-off thing, maybe arfcom classifieds are for you. But the member-base here is the memberbase that can afford to pay more money for more expensive things you may want to sell. Whenever I look for stuff to BUY here that I personally want, I rarely see things sitting past 2 months. Ive had arfcom listings sit for months, and Ive had stuff I bought there cheaper than expected because the bulk of the people sell the same cheap stuff there.
You want to sell $3 a round 6.5 creedmoor ammo you squirreled up on during Covid? this is the spot to find a buyer for bulk. If you want to do the same on gunbroker, $20+ in fees if/when it sells is gonna be the norm and you're still dealing with paypal transaction fees, or even worse, their GB pay crypto super secret squirrel 2 weeks in prccessing time gateway system.
As a "seller", this is a valuable audience you gain access to, with zero transaction fees, for $20 a month. If you buy and sell shit often, that $20 is a wash. Ive sold off a ton of ammo on Gunbroker, that in retrospect, I'd likely have made more money on, just selling here, and not paying countless final value fee and listing upgrades on.
Even outside of selling, this forum exclusively seems to offer incredibly valuable information that you cannot find elsewhere. Look at the MDT Oryx thread alone..the memberbase here is easily the best testing and feedback source across the internet for that product.