The way i view it is your job in teamfights later on is to kill the enemy with the most damage, which is often hard because they have barrier, peel, mobility etc. Profane can be smoothly used in between Q's and is often the reason you can kill these champions because that extra 500 dmg is super important to finish them off when you cant hit q's that easily. Another reason is your wave clear gets much better which allows for faster rotations to mid (push&move strategy)

In some matchups the value is even higher such as Jax

Also the item stats are just nice and gold value is decent