It dates back to UDK.
In UE4 there is an automatic padding generation, that is hardcoded to enabled by default. The principle, described in the article, is still applicable, when you are packing multiple UV shells for single object.
In theory, yeah, you would need it so, but on practice, you should just avoid placing seams of your modular assets on uniform surface. Hide it, preferably in geometry, or in a natural texture seam.
I’d also add from personal experience, that investing that much efforts with snapping lightmap UV to pixels and arranging perfect shell padding is often by far not worth time investments and quite commonly you can cheapskate on it by overpadding in favor of asset production time decrease, while sacrificing nothing, but small lump of lightmap space usage efficiency.