I argee animals are used for commercial or scientific purpose.

For now, people used animals to making food, or help inconvinient people(e.g. dogs for blinds) etc.

Why they're used animals as people's tool? I think they're useful for people.

Although they have emotion which is equal to people and living things, they have been useful and given many advantages to people since they're trained to people. It may be same for commercial or scientific purposes. Animals have been used to test many madicines already. consquently,  people are emancipated from many diseases. If it isn't conducted, many people may suffer from many diseases.

And the case of commercial purpose, by using animals for commercial purpose, people purchase more merchandise. that is, using animals for commercial purpose tempt people to purchase many merchandises. furthermore, it helps state economy, because it promotes consumption.

In this regard, I argee animals are used for commercial or scientific purpose. Thanks for reading.