Why are giants considered bad reinforcement troops?

you can't lightning dragons either.

5 or 6 archers will kill a giant fairly easily, whereas up against archer they usually aim for the same one and take a lot of hits as they reload to attack the next one.

Everything is way too fast for them

I only ask for giants when i know im going to be using giant healer strategy so I can save some time.
The main troops I go for are Wizards,goblins,and archers. I had only 5 goblins in my clan castle one time and since they are really fast, they ran to the giants the guy was using and smacked the ♥♥♥♥ out of them lol. And wizards splash damage the archers/barbs/goblins clumped up.