They're worthless. I would absolutely HATE to see even 5-minutes of developer time wasted on companions I never even see.
Going to have to agree with TUX.
At first they were interesting ..... 2 years ago when I first saw them.
Then, after realising how shallow the companion stories were and they were nothing more than combat bots and used in the worst crafting system i've ever seen in an MMO ever ....... I have zero interest in more companion content and would rather developer time be spent else where.