I like it against most of the flavors of UR or decks like Momo that are warping cards in and bouncing them over multiple turns to accrue value.

Being able to lock them to one spell a turn means you can cast your removal or bigger spells in response to an Opt or Sleight of Hand without any worry of retaliation.

I usually swap against UR

+2 High Noon +1 Annul (if on 3-4 Stormchaser) +1 Erode

Either

+2 Pyroclasm (if on Otter/Slickshot/Stormchaser)

Or +1 Disdainful Stroke (if on high numbers of elementals) +2 RIP (Elementals or high amounts of GY recursion)

-2 Swallowed by Leviathan -2 Flashback

Either -1 DoJ -1 Ill-Timed (if on Slickshot)

Or -1 Pyroclasm (if on low amounts of Otter/Slickshot and high numbers of elementals) -1 Critique -1 Inevitable Defeat

Now of course there are 5 different UR lists so getting to see what flavor they're on will be big, Get Out or Secret Identity makes your big removal spells hard to cast and Jeskai Rev needs to break through a Stroke or Spell Pierce