There are any number of reasons why a user may want to switch the model they are using for generation

• Newer models may be more prone to hallucinations and errors, since they have had less time to improve through feedback and QA
• On the other hand, newer models are more likely to contain updated references, making them a good choice over older models for low-risk research
• Commercially, they may not want to spend the money or tokens to use a newer model. Older models can be used to hone a prompt before it is applied to updated data
• Image generators appreciate the different aesthetics they can tap into with different models, much like someone may choose to listen to a specific album on vinyl for its aesthetic vibe despite the higher audio quality of digital recordings
• Some image generators enjoy remixing across models, capturing the aesthetics of one model, and then remixing it in a different model that might return more predictable results against their prompt
• For security reasons, users may avoid using certain models with delicate or proprietary data due to how the model provider handles this type of information
• Researchers, engineers, etc may want to move between models to compare results

Whatever the reason, we should assume that this emergent pattern will start to stabilize soon.

If you are working on an interface that allows for this setting to be changed, consider who should have that permission to change it. Companies may wish to restrict or enforce the use of certain models for compliance reasons.

Consider also that regulations related to AI are in flux. Be prepared for entire models to be restricted from use in certain geopolitlcal areas do to their policies.