Demonologist's Summon Ability

[Duvodas]

Hi,
I just tested the demonologist cause i never really considered them.
Was a bit surprised when i found out that you can't control their summoned demons. Why can you control all other summoned creatures, but not those demons?
That seems to be a huge handicap since you can't block narrows and they easily suicide attacking large enemy stacks. Can't they break spells like Blind too?
So why do you find this summon ability still useful?