They even provide a description in the UI of each before you select it, and it defaults to a model for you.
If you just want an answer of what you should use and can't be bothered to research them, just use o3(4)-mini and call it a day.
But I agree that they probably need some kind of basic mode to make things easier for the average person. The basic mode should decide automatically what model to use and hide this from the user.
It sounds like it means "have a bunch of models, one that's an expert in physics, one that's an expert in health etc and then pick the one that's a best fit for the user's query".
It's not that. The "experts" are each another giant opaque blob of weights. The model is trained to select one of those blobs, but they don't have any form of human-understandable "expertise". It's an optimization that lets you avoid using ALL of the weights for every run through the model, which helps with performance.
https://huggingface.co/blog/moe#what-is-a-mixture-of-experts... is a decent explanation.