I had a conversation today with Boris Leistedt about his work to build a latent model of galaxy SEDs and get template-space-marginalized photometric redshifts. I proposed that he instantiate the latent variables as observables (like rest-frame colors or line strengths or something); this will help the model break degeneracies and sensibly order the templates in the latent space. That is, it should regularize or simplify the model for inference. That's just an intuition. But it might also help people who have drunk less of our Kool Aid to understand!