White cards allow you to form a miniature army - your troops are numerous, organized, disciplined, and sometimes expensive. There’s also a pious, religious element that lends a hand - and is also pretty expensive.
White has the ability to stop just about any card, so it can slow the game down. Conversely, it also has many little recruits that can be somewhat aggressive.
White may be the second easiest color to play. You bring out a bunch of dudes, cast away the biggest threats, and then sing anthems, strengthening your team until the battle tips in your favor. If it takes a while for that to happen, that might be ok, because white is generally quite good at blocking (or temporarily arresting) - and if too much damage gets through, white can gain life to prolong the game.
The armies within a white deck are often masters of combat maneuvers, with training, armor, and sharp weapons (which sometimes carry the divine blessings that make monsters and demons become awfully weak). Magic design does a wonderful job at modeling the burden that these preparations take time and/or resources, but white creatures have speedy reflexes that take effect during battle, or discourage the other team from engaging directly.
If a combination of angels, lions, clerics, and infantry sounds like a reliable army to you, you’ll be blessed with white cards.