Ihave biked many caminos, walked some sections. I would somewhat agree with the above post, but it is relative to bike skills and experience. We have not had a flat for two years with my tubeless tires, the map is in the GPS on my handlebars, and we both bike like it is an extention of our legs. We talk to lots of pilgrims, walkers and cyclists.
You do get a longer look at things walking. Sometimes that is good, in the Meseta it is open to debate. Biking gives you freedom to push on extra km's to find the right place to stay.
I you are not skilled at mountain biking with a load, and don't have top quality gear, you might find it a bit of a struggle, at least to start,and that might dominate the "camino experience". For us, we love the simple life, with endless trail from one historic spot to another laid out in front of us, shared with an international group. We find that on our bikes just fine.
We are starting our Francigena ride today.