Some notes:
1. It's subtle, but some of the printed letters are formed differently than most Americans were taught in school. Look how the letters t, q, x, e, and E are made. The italic form of the letters looks better and feels more natural to write. (The italic number 5 was especially weird to me, but now it's impossible for me to write it the "old way.")
2. The article talks about this, but it bears repeating: the letters are formed the same whether you are printing or writing cursive. So italic can help you even if you insist on printing your letters only.
2a. But you'll almost naturally start joining some letters because it's faster, and joining other letters because it looks cool, such as any letter after an f or t.