you can see from the award chart that return economy to Europe is 100,000 miles.
return business class is 120,000.
at a 100% offer, the difference is about $350 to fly business class. that's on a return basis. for $175 each way no one would ever consider flying economy.
but lets look at the math... at 100% bonus your miles would cost you (at .94c to the USD) around $2001. you then need to add taxes of $150-200 or so.
you can get an early bird to europe on Singapore airlines for $1500 at the moment, including a free stopover (well, for $1 extra including transfers and hotels).
it doesn't make sense to use dividend miles for a Europe trip in economy unless you are really in peak season when airlines are charging $2500-2600. even then, to save a coupe hundred dollars? might as well fly business.
but on a business class award you're saving many thousands of dollars (around $2700 via USDM compared to minimum $5000-7000 on a mid range airline). even the cheapest business classes on someone like Garuda or royal Brunei are going to be in the region of $4000 give or take.