[levthedev]

Sure, if you think that rates are going to drop next year, and would like to secure the 10 year rate instead of risking that.

Another way to express it: if today, you believe the average rate over the next 10 years will be lower than the current 10 year rate, you should buy the 10 year treasury.

This is a tiny bit simplistic as it ignore liquidity/volatility differences between buying a 10 year treasury and buying 20 6-month treasuries or 10 1 year treasuries.