The more we invest in our security, the better we deter those who wish us harm.
If you are like me, and you don't believe Russia will attack a NATO or EU state in the near future... it opens up a lot of interesting hypotheticals.
Armed to the teeth, but with no Russian invasion forthcoming - what will the Western Europeans do? Satisfied that they deterred the Russians, do they just start to disarm again? Surely not.
So if they don't disarm, what to do with all the weapons and all the conscripts? The higher state of militarization may start to dictate its own logic.
Some hypotheticals:
1) Strengthened in their capabilities, Europeans take a more aggressive approach to North Africa. Under pressure from the Italians and other Mediterranean states, Europe sends forces into Libya - to prevent Islamists from controlling the country, and to curtail refugee flows.
2) France, smarting from being pushed out of places like Burkina Faso, Mali, CAR, etc by Russia - may begin to pressure its European allies for a larger scale commitment to West Africa. They may get support for this from Spain and Portugal. The goal would be to demonstrate an ability at defeating the Islamist insurgency that has eluded the Russians, and regime change (removing people like Mr. Traore).
3) With their large Muslim populations, Western Europe may try to drive a harder line in the Israeli-Palestinian conflict. Right now Israel only listens to America, because Europe doesn't represent anything from a security point of view. A bulked up Europe, could be able to make life more complicated for Israel. For example, by working closely with Syria and Lebanon, and applying pressure on Israel to deoccupy stretches of Southern Lebanon and the Golan Heights. In the same way, Europe could offer Yemen a way back into the 21st century, conditional on decoupling from Iran and not attacking Israel. For this, Yemen would likely require assistance in ending its civil war.
4) The most far-fetched thing I can think of, is that Europe may begin to compete with the United States for influence in the Pacific. Japan, Korea, and others are shocked at their treatment by a supposed ally, and are worried about being caught between two fires. Europe may offer a third way, where one does not have to be a vassal of either China or America. For this, it needs to be able to provide a credible security umbrella. So maybe Germans can replace Americans in Korea, and French in Okinawa. But this is fantasy land.