You can equip Geralt with loads of various armor and weapons in The Witcher 3. Usually, this is done based on the bonuses a particular piece provides, but some players may pursue their armor and weapons' good looks above all else. After all, a few extra damage or defense points become negligible with all the skills, decoctions and other stuff as you progress. Besides, wearing armor designed for melee specialists won't prevent you from becoming a capable Sign caster, though magic is still most efficient with the Griffin school set.