I see the advantage of inline navigation for the desktop is easy navigation since it's big screen. The links and important pages of your site are visible upon load. The downside, it uses large space and limited to screen width, or container width, hence, not good for menu that has ton of items.
As for button type menu (eg. mobile menu), you can have many menu items as it increases in height instead of width. And it's good for a site that has many sub-sections (pages) that are needed to be grouped.
Still, it's up to your design preference. Both types of menu are added so the user could design their own preferred layout.
Hope this helps.