From the Codex, regarding menu placement:

It is rare that a plugin would require the creation of a top-level menu. If the plugin introduces an entirely new concept or feature to WordPress, and needs many screens to do it, then that plugin may warrant a new top-level menu. Adding a top-level menu should only be considered if you really need multiple, related screens to make WordPress do something it was not originally designed to accomplish. Examples of new top-level menus might include job management or conference management.

I would prefer if Automattic would lead by example here - likewise with JetPack's menu placement.