No, I don't know why. But it's got to be down to finance and prioritising of budgets. I'm sure that the money for our Green Ways comes from some centralised EU fund. 'Green initiatives' are really high up in the order of priorities here and tend to get taken care of pretty swiftly.
I live in the Morbihan (56), central and southern Brittany - and apparently we're lagging behind the rest of France in terms of cycle lanes and other traffic-free cycle routes. But we appear to be much better off than some parts of the UK.
Ridden a few Voies Vertes of variable quality (some truly excellent, some that were clearly excellent at some point but had fallen somewhat into disrepair, and some which were unrideably bad).
That said, the riding experience even on busy, fast roads with no infrastructure is far superior to here - in France drivers clearly viewed me as a person and not an antagonistic obstacle to be passed as quickly as possible regardless of whether it's safe to do so or not.
Would you use it? Given the fact you have a lane either side of you, which I'll assume would have different timings at the lights.
Absolutely not. I'd take the lane all day long in that scenario.
This kind of infra is standard UK box-ticking dross - local authorities get to say that they provide x miles of cycling infrastructure and keep their grants while doing as little as possible whilst arguably making things more dangerous for vulnerable road users.