I started to use one with the idea of only using it now and then when I noted to find out something specific. I now use one most of the time, as I usually want to know what is happening to my BG. The most useful bit for me, is that in addition to my BG it tells me the direction of travel of my BG, admittedly I have to factor in a bit of a time lag as the Libre measures interstitial Glucose and the fingerprick is doing BG, but it helps me so much, especially as no two days are the same for me.
We decided that it was so helpful that we would rejig things and afford it for use all the time. I know that we are fortunate to have that choice, and I hope that the more people use them the lower the cost will come, and there are suggestions that it could eventually get onto the NhS list, but I think that that is very unlikely in the current climate.