Is the star rod useful?

It really depends on your preference of money making, and your fishing level.
I don't have one, but from what I heard, it makes around 10k with a decent fishing level.
The higher your fishing level, the more experience you get with each catch.

 

Yes, it is very useful. I think you can make $20k+ an hour.

 

I've been told 6-10k in fish, then around 5k in exp.

I think it's a nice new tool and while it dosn't make as much as other methods it's fun and new.

 

I guess that seems about right . I'm assuming about an 800+ fishing level and you can get $20k an hour though.