What benefits the Starship will bring? How the larger payloads and lower price for kilogram to orbit will affect us?
It's a cliche to talk about benefits the space advancement brings in general. Communications, Earth observations, medical science, technology are areas directly related to space programs. We can focus more narrowly on the aerospace industry, and here the changes are more pronounced. The key one is the following: in all times to make a controlled flight you needed to control the mass of the flown. Each kilogram of payload, from Montgolfier brothers designs to Burt Rutan ones, affected the cost - so much that we had to invent the ways to fly light. In 2010, to fly a kilogram to low Earth orbit meant to pay some thousand of dollars - maybe $10k, and that was if the payload wasn't people. And if the delivery is expensive, we'll try to deliver less, while still reaching our goals. Reaching goals with less mass both pushes the technological progress forward - and also adds to the costs not of the delivery itself, but to payload. Space-bound payloads cost more, per kilogram, than, say, houses and bridges, or even sea vessels. This leads to increase in demands to rocket reliability - as we don't want to lose an expensive satellite - which further drives the launch costs. A bad situation to be.
The reusable rockets, starting with Falcon-9, reduce the costs to orbit. They have their limitations, of course, but as soon as the kilogram to orbit becomes cheaper, there appears the incentive to build cheaper payload. That is, if a kilogram to orbit costs $2000, it doesn't make sense to pay more than $2000 to reduce the mass of the payload by 1 kg. Payloads become cheaper because we may afford to have them heavier. And since payloads are cheaper, we can better afford to lose some - we'll just launch a replacement, and if we can lose payload, the payloads become even cheaper. This happened before - in aviation costs of kilogram in flight also went down - and we can expect in spaceflight some similar results: we'll have more traffic to space. And more traffic from space. Larger space economics, with significant effects at least onto the aerospace industry. Not only that, of course...