With my WordPress integration I'm not sure it makes a lot of sense to keep BuddyPress. At the moment there's not really a profile integration, it's expected the only public profile is on the Flarum side.
If all the community features are on the Flarum side I would recommend using Flarum accounts and login exclusively and only use the extension to synchronise comment threads. But if your main business is based around a WordPress feature and the community is secondary, then I would recommend using the WordPress global login integration so your existing customers can join the community side with a single account.
If you are building a community from scratch and need to implement mostly custom features, I would recommend skipping WordPress entirely and use Flarum as the CMS/framework.