That's a very good question. It's too early to say. Short answer: yes (barring the unexpected).
Long answer: I've heard/seen mixed sentiments/implications from Famo.us, on where exactly BEST will fit in:
1) It brings in Meteor like features, so you won't need Meteor.
2) It will integrate perfectly with Meteor, so you won't need famous-views.
3) They're still pro community integrations with other technologies.
There's no question BEST is a must for raw famous apps. As I understand it you'll be able to use template like markup to create your components (like we do in famous-views) -- but I haven't seen it yet and I'm really not sure about anything So yes, you no longer "need" Meteor for these kinds of advantages, but, for any long time Meteor user, Meteor offers a lot more than just that (and is obviously a few years of work but an equally well-funded company), and I can't imagine Meteor users giving up Meteor in general (but could make sense for very small / lean projects).
Re BEST as a one-for-all integration, well, I guess it would be able to do a "naieve" mix of Meteor/Famous code in an app. I say naieve because very little of famous-views touches famous, most is the Meteor integration part. That's things like handling data context, integration of reactive helpers and cursors, modifying Meteor's timer internals, etc, etc. So for that reason, even befoer having seen BEST, I'm already working on the new version of famous-views and I'm very confident that it will stay.
So I think the most likely is the 3rd option, and, without having seen BEST at all yet, I'm quite confident that famous-views will allow you to use BEST code inside of Meteor (as opposed to BEST letting you run Meteor code inside of Famous). At the least, letting you use complete components written in BEST. Maybe integrating even further to bring the rest of famous-views features to BEST code, but I doubt that. Time will tell