whats the purpose?

I have heard of people doing something like what I list below but I have not personally tried it:

Toon 1
/targetenemyplayer
/cast <spell>

Toon 2
/targetenemyplayer
/targetenemyplayer
/cast <spell>

Toon 3
/targetenemyplayer
/targetenemyplayer
/targetenemyplayer
/cast <spell>

Toon 4
/targetenemyplayer
/targetenemyplayer
/targetenemyplayer
/targetenemyplayer
/cast <spell>