A single-edge sword is stronger because the dull side is thicker. But "the enemy" can grab the dull side and take it away.
The double-edge sword is better at thrusting, piercing through armor, and no one is going to grab the blade. But the downside is that it is subject to breakage because both sides are thin.
The double-edge sword requires more maintenance having to sharpen two sides rather than just one
Is it best to have both?