I recently flew Delta from Detroit to Tokyo. The flight itself netted me 13,700 miles. Since I am in the Chicago area, I do not fly Delta ever.

Because the entertainment system was malfunctioning, I was offered a $200 voucher or 20k miles.

Which provides more value for future travel? Basically, what will get me further, $200 or 33,700 miles? I would imagine that one has more flexible routes?

General advice appreciated.

Thanks,
Dan