For now there is only two models at https://huggingface.co/models?filter=onnx 7.
And I agree with @bdalal, it’s “quite easy” to convert a model to an onnx checkpoint and use it in let’s say NodeJs which don’t have a mature ecosystem for Deeplearning.
I would convert them it if I need to fintune a model but for hub models it would be more convenient to download them directly (if converted automatically). I almost envisaged to convert the models I use and host them for my team to use…
Also a model.save(args, onnx=True) to save a onnx file locally (by calling convert_graph_to_onnx) as well would be really useful !
So here is the 2cents of a really happy user 
Thanks for this wonderfull tool !
Have a great day