I know that the use-case that I mentioned as well as many of the agentive aspects can be achieved using code. But I have to admit that using the UI and easily create GPTs, whether using them just as templates/personas or full-featured with actions/plugins, makes the use-case much easier, faster, and sharable. I can just @ at specific GPT to do something. Take the use-case that Simon mentions in his blog post, Dejargonizer, I can have a research GPT that helps with reviewin papers and I can @Dejargonizer to quickly explain a specific term, before resuming the discussion with the research GPT.

Maybe this would require additional research, but I think having a single GPT with access to all tools might be slower and less optimal, especially if the user knows exactly what they need for a given task and can reach for that quickly.