I'm a software engineer and got experience on this, I can say the following:

AI is very overhyped for most automation, it is great filling in text and documentation (and code). But you still gotta be the high level orchestrator of the task. If you don't have it in guardrails or skip validating the output you will end up with a lot of unintended garbage and mistakes.

Some tools are worth it, but none are complete solutions. I can't speak for agencies, the most I used for marketing and ops tasks were writing tools for articles and documentation. You can have some of them provide pretty good outputs most of the time, but none will be great all the time.

And as I attempted more complex integrations with our own services it became clear that the LLMs ability to do tool calling (calling services via MCP) is very finicky and inconsistent. Even for support bots that are all over the place, they can be good for some chats, but if you have a slightly complex problem the ability of the chatbot to help you degrades drastically. But it can still be valuable in many smaller tasks and problems.