No, you don’t need to have a Multisite website to use BuddyPress. BuddyPress can easily be installed and can be used in any kind of WordPress enabled website.
Do I Have to Enable Multisite to Use Buddypress?
Update on March 17, 2020
No, you don’t need to have a Multisite website to use BuddyPress. BuddyPress can easily be installed and can be used in any kind of WordPress enabled website.