Short answer: if you're swapping threadless jewelry yourself, yes, and it's one of the cheapest things in your piercing kit that actually makes a difference.
The Problem With Using Just Your Fingers
Threadless jewelry stays in place because of tension, a small bend in the pin grips the inside of the post. Every time you pull that pin out with your fingers or a pair of pliers, you risk bending it slightly out of shape. Bend it enough times and it stops holding as snugly as it should, which means loose jewelry that's more likely to fall out.
Then there's the practical side. Threadless pieces are tiny. Trying to line one up by feel, especially in a spot you can't fully see like the back of a helix or a rook, usually ends in a dropped piece, a scratched ear, or both.
What the Tool Actually Does
A changing tool is basically a slim taper that acts as a stand in post. You slide it partway into the piercing, set your jewelry on the tip, then push it the rest of the way through so the jewelry seats itself without your fingers ever touching or bending the pin. Removal works the same way in reverse. It's a small piece of gear, but it takes the guesswork and the fumbling completely out of the process.
Why It's Worth Having
If you've ever bought a piece you loved and had it stop sitting right after a few changes, this is usually why. A tool protects the pin, which protects the fit, which protects the actual jewelry you paid for. It also makes solo changes realistic for placements you'd otherwise need a second person or a mirror gymnastics session to handle.
We keep ours priced at $8 for exactly this reason. It's a small add to your cart, and it pays for itself the first time it saves you from bending a good pin or dropping a piece down the sink.