Rating improves your own understanding of IF, and can prove to keep you on the ball even when not getting real IMC to hone your skills. Is it worth a grand? So far I have done about 40 hours training, but do not get any extra payment above normal PPL rate...so it has not paid off financially. But would recommend it as keeping progressing as an instructor.
Do I recommend it to my students? Only the good ones who you know will not struggle with the mental dexterity for ADF tracking etc...and can fly an aeroplane on height and track without devoting their entire brain to the task.