I put mine in the keg or fermenter, also works great with coffee beans, cacao nibs and etc....
Sure, a small amount of hop particles are going to come out of the holes, but not that much.
I toss my hops into the boil loose, adjust my volume and accept 1/2 gallon of hop sludge at the bottom of the kettle as waste.
Hops are more expensive than making an extra 1/2 gallon of wort, so I toss them in loose. There are hop screens available for use in the boil.