Most people find kf&b easier, that's all. If you want to do M1 for this type of increase, go for it. It actually will be more invisible than the kf b.
If you think written directions would be easier to follow for f&b, just knit into the stitch as you normally would, but don't slide it off. Bring your needle between the two 'legs' of the stitch and insert it in the hole of the loop. Wrap your yarn and bring it through. Then slide both off.
But in this case, either will work.