Question about "default weapon attack"

Hi guys!
Straight to the point. Are phantasmal blades with modifier considered “default weapon attack”? I`d like to use recently buffed Demonslayer set but dont know what to choose as secondary mastery Occultist or Necromancer. If reaping strike and another passive proc of phantasmal blades than the choice is obvious. If not then there is not much of a point in Necromancer.

And can they proc of any skill with percantage of weapon damage?

Phantasmal Blades are not a default weapon attack replacer.

The replacers off the top of my head are Cadence (Soldier), Savagery (Shaman), Fire Strike (Demolitionist), Troll Rage (via Mistborn Talisman), Beronath’s Fury (via Shard of Beronath), Runic Bolts (via Runebinder’s Spellthrower) and Fleshwarped Strikes (via Theodin’s Scepter). We also know Forgotten Gods will introduce another in Righteous Fervor (Oathkeeper) when it releases and another through the Rah’Zin armour set.

Edit: Forgot about Belgothian’s Strikes (via Belgothian’s Slaughter set).

Check the skill’s tooltip/flavour text and it will mention in orange text that when it is used it acts as a default weapon attack replacer.

Okay. Thanks alot.