If you’re doing outbound marketing to try and sell a domain name, you might want to remove its buy it now landing page first. If you don’t, closing a sale could cost you quite a bit of money.
If you’ve targeted the right prospective buyer(s) for your good domain name, you will generate interest in the domain name. The first thing a buyer might do is visit the domain name to see what’s there. If you have a BIN landing page showing, the buyer might proceed with the purchase without even responding to your email. While this is an okay problem to have, you’ll still end up paying more in commission for this deal.