You might prefer an option found in the Editing: Options tab: Open comments in inspector if possible set to off. In this condition, with the inspector closed (as it sounds like you have it), footnotes will come up in a pop-up when you click on them—and that includes when you create them as well.
You can tap Esc or click anywhere else to get rid of the box, and you don’t have to sit there and wait for however many seconds it takes for a tooltip to appear to begin with. Plus, you can edit if you spot a mistake, rather than spotting a mistake and then having to click and open the inspector, fix it, then close the inspector.
The interface will still use in the inspector if it is open to the Footnotes & Comments tab—after all, it’s right there—but in all other cases you’ll get this format.
That aside, I also echo a bit a confusion over why you are using Footnotes for this instead of Comments (which have the same exact set of features, save for also being capable of colour-coding). And unlike footnotes, by default they will never be exported (and if you really want to export them as footnotes, you can actually do that, so there is no downside).
If you do ever change your mind, it’s no big deal either:
- Select Draft or some other high level folder.
- Switch to Scrivenings view.
- Open the Inspector to Footnotes & Comments.
- Click anywhere in the sidebar to move the keyboard focus there, and press CtrlA to select all of the footnotes.
- Right-click, and “Convert to comment”.