Indestructible creatures and recursive threats all get exiled cleanly
A commander can be cast from the command zone for its normal costs, plus an additional two mana for each previous time it's been cast from the command zone this game
It's a key part of Red card flow, and there are entire Commander brews built around Wheels
Table of Contents Ultimate Guide to AFR Limited and Prerelease Chapter 1 - Top Commons for Limited and Prerelease Chapter 2 - Top Uncommons for Limited and Prerelease Chapter 3 - Guide to Combat Tricks and Removal Cards by Colour Chapter 4 - Guide to Dice Rolling Chapter 5 - Guide to Dungeon Venturing
They give you some early-game value but become quite explosive when exiled with Ellie and Alan to discover X, where X is the mana value of the exiled card
Whether it was flashing back a counterspell or a Glimmer of Genius, the ability of Torrential Gearhulk to shift gears, turn the corner, and close games quick while also providing huge card advantage was a very powerful tool