Some people do not know what this is. Are you "getting paid" with a promise of future credits, or literally test tokens on a testnet which are not originally intended to have value?
You get rewarded with testnet tokens which can be traded when it get listed on exchanges. It’s called “test network” because basically you get rewards for testing and experimenting apps and network upgrades.
I guess the definition shifted. Usually it's known as coin/token that supposed not to have any financial/monetary value. Anyway, it doesn't change the fact that they don't want to pay professional tester either with fiat or popular coin where they pay amateur tester with their own token that probably have little or no value.