It has some rudimentary version of the principal characteristics of a cycle lane and with the right conditions might actually develop into a recognisable cycle lane but it's vulnerable and liable to be killed.<-like this analogy
Part of the problem with the scheme stem from its evolutionary nature. Swathes of tarmac are now "pedestrianised" but they still look like road (unattractive surface and subconscious "danger area") and there is little to attract people onto them, so they remain empty. In fact, the restaurant pavilions actually discourage peds from using it as they completely block it in places.
As a result, I'm not sure peds appreciate the extra space (especially outside Le Monde, where use of tables, chairs and sandwich boards on the pavement next to a pavilion mean that the ped-space is even more confined than it was before).
For my part, I'm making a point of strolling on the road to encourage others. To be fair, I've been doing the same on St Andrew Square and the vehicular side of George Street, but it's a lonely walk.
Public realm improvements would mean this would have a much greater impact - for instance, resurface *all* of the block in front of the Assembly Rooms to make it look like a public plaza that car driver are guests on rather than owners of - but I recognise that it's difficult to justify that when you've dressed the whole thing up as an experiment so as not to frighten the horses...