Its just like on the roads.... having some consideration for those behind you, if you chose to travel slower than 'average'. 180 at 25 miles may not be dangerous, or illegal, but it is inconsiderate, if you have been put at the front of a queue.
Too may people are not familiar enough with how fast you can slow the aircraft with gear. eJ over-SOP's philosophy denies most new recruits the concept of using gear gear before flaps if it helps in the optimum descent. I get really frustrated when FO's fart round with speedbrake at 180/190 (A319) when dropping the gear is an instant cure.