Yeah, the cracks are closed permanently.
Let's be clear; the cracks in my guitars were caused by severe drying out of the wood due to New England winters and baseboard heating. Sigh.
Anyway, it dryness is the reason for the cracking in your guitar, then when you humidify the guitar, it will gradually swell back to it's normal shape and the cracks will seal themselves. It's permanent as long as you keep the guitar properly humidified.
The cleats are advisable if the crack is just big, or in a location on the guitar that gets some stress -- like near the neck.
Here is an example of a cleated repair on the mahogany back of my 12-string (the neck block is at the top of the photo, looking in the soundhole:
