Mosaic knitting - why?

Ok, mosaic knitting, people. I am trying to get my head around it with Barbara Walker’s book. I don’t see the magic. Isn’t it just a fairisle designed so that each row repeats so you can knit one colour for two rows, slipping the other stitches, then go back and knit the slipped stitches in the second colour? I don’t see that it is ‘floatless’ except by choosing designs with small floats. An I missing something here? Otherwise it just seems like extra work because I have to handle all the stitches twice, first slipping them then knitting them. I can still pull the floats too tight. I love the designs but I don’t see what is special about doing them this way rather than as fairisle. I’m sure I’m missing something here.

Thanks!

On the mosaic hat I did once the beauty of it was that you never had to carry the yarn across. It was one row of color at a time slipping colors here and there. So it was floatless.