Initially, the LPT is being staked to earn new issuance (“inflationary”) subsidies. That means that the LPT supply will increase and stakers will capture the newly issued LPT. Generally, you will earn around 20% annually on your staked LPT, but that can change. Since staking rewards are tied to inflation, read about how inflation and rewards are related here.
Stakers will also capture fees from network transactions, so as Livepeer transaction volume increases, LPT stakers will earn more than new issuance subsidies.
The LPT also gives stakers the right to vote on policy decisions for how the Liverpeer will operate and distribute treasury funds.