Only if you have NO other way to create and scale graphics (unlikely if you have a color inkjet printer). The included software is very limited with only a small number of graphics until you "upgrade" to the full version for a further $9.99. Along with the minimal software, you also get a 3oz spray can of "decal bonder" (to keep the ink from bleeding) and only one half-sheet (5.5” X 8.5”)each white and clear decal paper. The decal sheets come rolled up in the box so you'll have to flatten them out under a book for a few days before trying to run them through a printer.
A better alternative might be to just buy the blank Testors decal paper you need and buy a can of the Testors decal bonder.
BUT - think carefully about how you'll actually USE any of this. You can't print white - you have to use white decal paper for that. And if you use white decal paper, how will you cut the tiny decals to be smooth, even and symmetrical along their edges? Not impossible but certainly not easy either.
Best bets are printing monochrome lo-visibility USAF/USN/USMC markings on the clear paper.