Membership 2 Pro VS Pre Sites plugin, if have Pre sites plugin, is still need membership 2 pro?

Dear Sir,

Is Wordpress.com and your sites, is just use Pre Sites plugin or both?
If have member service, have pre sites plugins, is still need membership 2 pro?

Membership 2 Pro VS Pre Sites plugin, if have Pre sites plugin, is still need membership 2 pro?

Membership 2 pro could use in the MLM system or not?

Thanks!