Should I use BMM & Exact match for the same campaign?

Not in the same adgroup. But, for example, should I use +running +shoes in 1 AdGroup, then add it as an exact match in a different campaign. I fail to see the advantage of this, beyond possibly improving QS.

ThoughtS?

 

There is no advantage in doing this. You can put all match types in one group which is what I've always done.

Any QS improvement will be an illusion. Most people I know who split groups or campaigns along match types use the same ads. If you are going to do this, use different ads. But that's a lot more work so they don't. Plus, how can you create an ad geared to the match type, if that is part of the strategy? I see no way to influence a click (and sale) for "round plastic widget" vs [round plastic widget].

Realize too that Google does not make any distinction between match types, they are all treated the same. That's why in a group of the same keywords in different match types, the QS are all the same.

Finally, you are making your campaign size 3-4 times bigger. Not an issue with a small campaign with just a few ad groups. But when you get to hundreds or thousands, it becomes harder to manage not to mention comparing say the phrase match group to the exact.