On production side, there is a wider range of yarns you can use. Printed ties are usually made up of silk, knitted ties can be wool, cotton, silk, cashmere, linen...
Using all these different yarns you can reach tones of colours and shadows you can't reach with printed silk.
Of course the knitted tie is more "casual" compared to the regular silk ones.
My father was used to produce thousands of knitted ties in the '70 using our socks machines.
For long time they were not so popular here in Italy until 2-3 years ago. Now they are very fashion and all the major brands have them in collection.