Most of the value in agentic development IMO is in the feedback loop/ability for the model itself to intelligently pull in context, but if you want to push a lot of context or have steps that are more proscribed, it's kind of a waste of money to have the big model do that. Much better to use it as a kind of pre-processing/noise-reduction step that filters out junk context.
I would say that right now the benefits are largest for this kind of work with medium-sized multimodal models. For example I have hooks/automation that use https://github.com/accretional/chromerpc to automatically screenshot UIs and then feed it into qwen-family models. It's more that I don't want to pay Opus to look at them or remember/be instructed to do that unless it goes through QA first.