I was reading Mordenkainen's Tome of Foes when I stumbled on an interesting turn of phrase (it's repeated often in the book and in others, but this was where I first realized it).
The Demonic Boons section lists the following trait for followers of Graz'zt (p. 30):
Joy from Pain. Whenever this creature suffers a critical hit, it can make one melee weapon attack as a reaction.
Meanwhile, in Xanathar's Guide to Everything (p. 46), the Mastermind rogue's Misdirection subclass feature says:
When you are targeted by an attack while a creature within 5 feet of you is granting you cover against that attack, you can use your reaction to have the attack target that creature instead of you.
Is there any mechanical difference between these two phrases? If something is done "as a reaction", does it not "use your reaction"? Or are they just interchangable phrases?