In fact the Ilford Multigrade Filter Kit is just a darkroom equipment for the black&white printing.
I've got two kits:
_ one kit is numbered 00-5 in 1/2 steps
_ the other kit is numbered 1-5 in 1 steps
But like you can read at the Ilford website: "However, there are very good reasons why you should still [...] use MULTIGRADE filters."
And before I will use them in the darkroom, I've used them as normal filters.
First I've used the 3 1/2 filter in combination with the Metz Mecablitz 20BC6 at my Praktica LTL3:
It's very easy to use, here a picture:
"zenit in pink", brasil, 2010
After that I've used the other kit. Here I've used the filters 4 and 5 together at the Praktica LTL3 and the Exaktar SFX 35:
Because of the filters I've exposed the ISO 200 film like an ISO 100 film.
Here a picture:
"confusity", brasil, 2010
And yes, Ilford is right! There are very good reasons why you should use MULTIGRADE filters in the darkroom and at your camera and flash!