I could imagine ‘vendors’ who provide complex stacks utilizing a lot of services (like an ERP system i.e.) might be the ones to be interested being able to provide/maintain their own container image.
Maybe the way to go for such would be to provide the infrastructure required (with as little resources as possible spent on that) for such a ‘hub’ by the LXD team and then just see whether ‘vendors’ (which may be other distributions as well) may make use of it.