Whether to come out or not depends on lots of factors such as how close you are with your family, how troublesome it would be for you to come out, how prevalent your bi-ness is in your life, etc. For me, I am gay all the way, and I couldn't take being in the closet anymore, so I had to come out to my very religious, very homophobic family for myself. It was rough for a lot of years, but I'm much happier having done it. But, my being gay is very pervasive in my life, especially now that I have a partner, which I did not have when I came out.
For example, for someone who is trans and seeking to make the transition, and who wants to see their family at any point in the future, it is impossible not to come out because your family is going to know you became a dude when they see you. Plus also, people talk, and you would not believe how talk can travel between people who seem to have no connection to each other.
But for someone who is bi, who isn't close with their family and/or isn't seeing anyone seriously, it may not be necessary to put themselves through the anguish. Coming out can be painful. A lot of people live 'out' in their everyday lives, and then in the closet for the once or twice a year they see their family.
I generally advocate that everyone should come out, but I am very biased for total honesty in all things. Life would be much simpler if everyone was honest all the time. But if only one person is honest, that can complicate things. It really has to be your own decision. I couldn't take lying anymore. I felt like I would die or kill myself or kill someone else if I had to be in the closet any longer. But I have a cousin who is bisexual, and he hasn't come out to the family (except me) because that works for him. He isn't seriously dating a guy, so there's no reason right now to tell anyone. He said that if he falls in love with a girl and marries her, there wouldn't be any need to ever tell his family he also likes guys. And if he falls in love with a guy, he can come out then.
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You don't need to hide, my friend, for I am just like you.