Posts / All posts of the site e.g.
( posts/nalle-puh, posts/big-bad-wolf, might be from 10 - (500-1000) subpages );
Pages / All pages of the site e.g.
( pages/projects, pages/projects/commercial, pages/projects/editorial, pages/contact, pages/about );
Then i assign each page in posts to a page in pages(category) e.g. (pages/projects/commercial), and do some fancy routing to get it to work.
So my question is how many subpages can you have in a page before it starts to slow down in load time, is there any smart way to “archive”, perhaps you can do some sort of “auto archive” in a hook, like posts/month-year/nalle-puh ?
Conclusion: It depends on your site. What I recommend is to create as many pages as you expect using a script and check if the site is slower afterwards. Nothing better than a realistic benchmark of your own site.
yes, more freedom, pages is for the site structure and posts to fill the site with content, faster publishing, more control(oversight) and more flexible.