The healing aura is replaceable to discretion, but if you're doing campaign farms for shards fighting on the top bridge makes you essentially invincible if you're not confident enough in your raw DPS output, you might need to split screen multiple heroes to set up everything on a single 4DU stack, but if you're really struggling there's an extra DU available so you can stretch the buff beam to 5DU no problem

I recommend if levelling to hide the heroes being levelled underneath the bridge you're setting up on, which is the middle bridge between the 2 crystals

Works for both campaign and survival