Not if you are just looking to be discovered. The truth is that the road to discovery is long and winding and probably doesn't end at an open mic. Why? Unfortunately, talent is not the only factor that causes people to be discovered. That factor that most people are looking for is crowd draw or fan base. They want proof of success before they invest. Open mics do not provide that proof since you are not the headline act and the crowd is there to be able to sing, not to hear you.
However, there are probably several open mics along the way on that road to discovery. What do I mean? My family is planning to drive down to Florida, and we realized that we did not want to try to fit it all in one epic drive. We booked a stop in Georgia on the way down and Virginia on the way back. Instead of barreling straight down to our destination (and exhausting ourselves in the process) we are taking our time and enjoying the ride.
How can we enjoy the open mic ride as performers. First of all, we can actually listen to the other performers. I know a lot of them are bad, but use that as a way to boost your confidence. Plus, some of them are good enough that you may want to celebrate with them. You may meet a future band mate, the person who will help lay down a track on your next album or a person you can share gigs with. One of the main goals of open mics is to meet and connect with other performers. We can accomplish more together. Plus, when you show people that you are interested in their performance, they will be more interested in listening to yours.
This leads to the next point. Another major goal of open mics is getting your music heard. The more people hear your stuff, the greater chance you have of building a fan base. If you have talent, then there are people out there somewhere who will enjoy your music no matter what style it is. The problem is that there are so many people out there and getting them to hear your music amongst the sea of other performers is hard. The more your songs are played (live, radio, internet, wherever) the better your chances are of connecting with your fans. However, that connection won't happen if people aren't listening. Even if the other musicians at the open mic aren't your perspective fan, their friends and family may be. If you make enough of a connection, they may be willing to connect with you on social media (giving you access to their friends) or even tell others about you.
Open mics can either be a drag or a lot of fun. It all depends on your perspective and attitude going in. We know that they are not the final destination, but they can be a fun pit stop along the way. Let's make the most of every opportunity and have an open mind at open mics.