Why would I want to train defending attributes in strikers?

[jklm_37]

And vv...why would I want to train attacking attributes in defenders/goalkeepers?

Also, for MCs...are they at best when their attacking and defending attributes are balanced?

As far as im aware yes concentrate on defensive & physical for midfield and defence while it's offensive & physical for strikers...

But...

You also need to add some skill to their weaker areas so that the players overall skill level improves...