I’m a big fan of 650a having accidentally built up a cheap 10 speed with this wheel size. It was a city beater and I didn’t know any better at the time. I was planning to build up my next commuter with this size so it’s nice to see how good the Peugeot looks.
In my perfect world, the 650a size would have been chosen to revive, considering that it was an already well established old standard, so tires can still be found in a pinch at the Walmart’s of the world. It’s still used in Japan on touring bikes, and also happens to be the standard size for wheelchair tires. A 3mm reach difference vs 650b doesn’t sound like much but can make the difference between using long reach brakes or having to resort to much more serious modifications.