Sometimes before allowing members to start trading on a marketplace you need to verify their identity to reduce the chances of fraud. Fraudulent buyers can get your Stripe account cancelled due to charge-backs/stolen credit cards. Fraudulent sellers will mean buyers may not receive their order and request a charge-back.
Verifying the identity of users means members intent on using stolen cards for instance can be weeded out. While you can cancel and refund transactions, it is a lot of hassle for you as the marketplace owner.
Once you’ve enabled the add-on you can restrict the ability to browse listings, post listings and place order to verified users only. This is all in your settings panel.