I always booked them when I was traveling with the family, Mrs. was also gold, incase the immigration lines were long. This would save us having to stand in long lines if we arrived after other Asia airlines.
Also good for your first time arrival for them to take care of your visas.
However, I never used them when either I was traveling alone or only with the Mrs. as we have e-gate and get through faster than using Al Maha.
You can also use it for departures but again I think it is only useful if you are traveling with families.