Not necessary & I find it a waste of money to do so but again it's up to individuals. I just asked my immediate family members to guess my baby's gender via WhatsApp. Still exciting though. I didn't even announce my pregnancy to friends or social media until I am 8 mths pregnant.
I'm also contemplating to do it or not. My friends are more excited than me to do gender reveal. still not decided if I should do it but if we were to do it, I think I will just invite close friends. Parents, parents in law etc we will just tell them verbally.