I've just walked from Le Puy to Conques in walking sandals, and it was fine. Walked from SJPdP to Burgos in walking boots last year and got dreadful blisters.
Olaes, you are most likely back home by the time I am writing this, but since these threads stay up and others read them here is my experience.
1st Camino: wore Merrell shoes that resemble this year's Mimosa Ginger Model. Loved the fact that I could remove the back strap if I got a blister and still had a good trekking sole. And they have good ventilation. But the ball of my feet hurt and the days ended up being quite long.
2nd Camino: bought gorgeous, light, memory foam-lined Mamuth hiking boots. Ball of foot hurt so much that on morning 2 I tied them to my rucksack and put on my slip-on Crocs. And by slip-on I mean they look like the old Dr. Schols sandals, the one with wooden soles and a single leather strap. Yes, you read right. It was heaven! This was starting in Hospital and walking to Astorga where I found a trekking equipment shop and bought Northland trekking sandals, that only had 2 velcro straps but a high arch. Loved it, and didn't mind getting my feet wet in the Galician rain since my feet would dry in an instance.
3rd Camino: having been diagnosed with flat feet, hence the pain on the ball of my feet, I opted for a pair of Columbia Gortex trekking running shoes in which I would put my prescription insoles for my flat feet. Heaven!
So ... pain is not something you need to live with. Boots that weight too much and cover your ankle: not needed either. Light, with a good sole, and the proper structure for your feet is ideal, although walking, in dry weather with my slip-on Crocs was, as incredible as it sounds, just fine. Because I need to wear my Rx insoles I will stick with a shoe in which they can fit, but other wise, the Merrel and the Northland sandals were just fine.