GPM vs GMV: Which Metric Actually Matters
GMV is what a creator sold; GPM is how efficiently they sold it. When you are choosing who to work with, the rate tells you more than the total.

GMV is how much a creator sold. GPM is how much they sold for every thousand views. Both matter, but for a different question. GMV tells you what happened. GPM tells you how efficiently it happened, which is closer to what you need when you are choosing who to work with.
What each number answers
GMV is a total: sales volume, with no sense of how much attention it took. A creator with a high GMV might have earned it from a huge audience, or a small one that buys. GPM is the rate: revenue per view. It shows whether the audience converts or just watches.
Why the difference decides picks
Two creators with the same GMV are not the same bet. One gets there from a million views and a low GPM; the other from a tenth of the audience and a high GPM. The second converts harder. If you are picking a partner, the rate is the more useful number, because it travels to your product better than a raw total does.
Which to read first
Read GPM before GMV, the same way you read conversion before reach. A high GPM says this creator turns views into sales, which is the thing you are buying. GMV confirms the scale. Start with the rate.