heck no. terrible. Ever run xc? 5 mile tempo at threshold pace. You want to run this as fast as you can without lactic acid in your legs. If you are in good shape for 5000 meters, you should be able to do a 3 to 5 mile tempo.
I never get these guys doing "tempo runs" at slower than hm pace. you can do hm pace workouts for 7-8 miles, no breaks. why go slower than that and shorter?
if you are training for a hm or marathon, sure, do a slower tempo, but do it longer, like at least 7-8 miles.
A 4 mile tempo, break, hard mile for a 18:40 5k guy could look like this:
4 miles at 6:20-6:30
break (say 5 min?)
1 mile at, say, 5:40-5:55, perhaps faster