I also know that because it’s open source, if I ever have a need to, I can host it on my own servers. Currently I don’t have that need, but it’s nice to know that it’s in the cards.
OpenAI just went through an existential crisis where the company almost collapsed. They are also quite unreliable. For some use cases, I'll take a service that does slightly worse on outputs, but much better on reliability. For example, if I'm building a customer service chat bot, it's a pretty big deal if the LLM backend goes down. With an open-source model, I can build it using the cloud provider. If they are a reliable host, i'll probably stick with them as i grow. If not, I always have the option of running the model myself. This alleviates a lot of the risk.
If you carefully craft and evaluate your more complex prompts against a closed model... and then that model is retired, you need to redo that process.
A lot of people were burned when OpenAI withdrew Codex, for example. I think that was a poor decision by OpenAI as it illustrated this exact risk.
If the hosted model you are using is open, you have options for continuing to use it should the host decide to stop offering it.