If you think it's stupid, you don't have to do it.
Oh, the beauty of TES.
This ^
I think they should take it further. You should be able to train offensive skills on test dummies, but at 1/3rd the rate.
I was waiting for a certain time of day outside the companions area, decided to take out my bow and arrow for some practice. I play first person without crosshairs so I have to use the notched arrow as a pseudo crosshair (which actually works, the arrow doesn't go level over the crosshair anyway so you have to guage distances, and the arrow goes straight over the tip of the notched arrow). I shot at the dummies in the courtyard until I could hit the targets dead center with 3/4 of my arrows from across the courtyard, I could hit all 3 of the small targets of the target with 3 4 inch targets as hands/head one by one, and I could double tap each of the 3 other dummies in rapid succession while on the move (hitting the 3rd one in the neck and shoulder where the armor is weak, bypassing the shield/helmet/sword). For all this practice, I got no experience.
Honestly it seems weirder you can't gain XP by practicing moves/accuracy than it does you can skill up on your horse.
(while on the subject of arrows against armor, anyone else think it would be a cool mechanic/talent for dual weilding to be able to both deflect arrows and deflect power attacks why doing a power side attack with 2 1-handers at the right moment? I think you should be able to TBH... modders go nuts)
In the end? It's a SP game. If you don't want to use the dummies, you can level up the old fashioned way... but if you want to RP as a trader/smither that practices until he is in some of the best armor out there while traveling around trading with other cities and only starting the main quest when everyone is in epic leveled gear... why shouldn't you be able to? It's the main reason I almost always leave the main quest till the end of the game. Ever since ES games have been leveled, it's much more epic fighting enemies in magnificent armor and fully formed daedric soldiers than scavengers in iron/fur or scamps... I mean, the fate of the world is at stake right?