Wands are good for one thing and that's fine-tuned control, They are the scalpel of magic, Wandless magic is a lot more wild and much better suited to broader strokes, want to make something explode? With wandless magic, you could put up a decent siege on a castle but with a wand blowing up a wall or door is all you get. Turning people's blood cells into needles? With a wand sure it's possible if a bit finicky but wandlessly you'd have more hope just removing the blood entirely and I mean that literally. This is important because the more you use Wandless magic for little things or detailed tasks, the more you're wrangling your magic to do what is essentially killing a fly with a nuke.