Experienced in what dimension? I've been using these tools for about a year and coding for 20+ years, and frankly these long horizon tasks are the OPPOSITE of what I want. I want quick iteration cycles so that it doesn't spend a lot of time and tokens building things I need to throw out. I think the people that mostly want long horizon tasks are: AI labs, because they want you to spend tokens, and vibe coders, who are mostly using it for entertainment purposes.
I don't know about the overall breakdown but in my case longer runs are prototyping, bug hunting, reverse engineering, etc. For example Gnome Remote Desktop didn't work in my configuration due to a combination of hardware and codec bugs and settings. One drive to make it work, another to backport the current upstream packages to Debian stable, restack the patches, and push to my machines. Another sequence of long runs was writing a new client for a closed-source conferencing service I use to allow fixing some particularly irritating bugs. Exploit development has the same shape although that's not something I do personally. From what I've seen the amount of useful hands-off run time is directly related to how clearly it's possible to specify a concrete, verifiable standard by which to judge the outcome. For some tasks that might be days or weeks, for forward engineering on a software product that for me is usually under an hour.
I work on systems code that is tricky to write, but with a good test harness. Being able to leave the agent unattended to try several paths when I'm generating the first draft of some code is very helpful.
Of course beating the code into shape for submission requires more manual work. But the draft stage is valuable to find unexpected friction points.