In contrast, rocketry seems practically easy, it's just an engineering problem in comparison. You exercise literally trillions of transistors just to send an emoji to a friend, and yet the modern world we've built makes all that seem trivially easy. Not because it is easy, but just because we've invested a ton of effort into building and optimizing every bit and piece of it. We're already on some Nth generation of smartphones (retina displays, quad-cores, GPUs, LTE, etc, etc, etc.) whereas we're really not on that many generations of rockets, certainly less than a dozen, maybe only half a dozen depending on how you count. Once we get rolling with reusable rockets the iterations on development will speed up and we'll progress faster. And we'll get to a place where what seems like an adventure into the barren wilderness today will become merely routine and ubiquitous. Just as today using computers or flying on a jet aircraft thousands of miles seems routine and ubiquitous.
As for the benefits of space exploration and colonization I expect a lot of them will come in ways that people won't expect. A greater appreciation for what we take for granted here on Earth, for example. A tree on Mars is a treasure to be protected and revered, as is clean air and water. On Earth it's not much different, but we don't take care of the gifts we have to the degree they deserve. We dirty our air and pollute our water, we overfish our oceans, etc. Similarly, advanced off-Earth habitats are going to need to seriously invest in things like renewable energy, energy storage, recycling, end-to-end stewardship of the "CHON-cycle", and all that stuff. Here on Earth we can be reckless and treat topsoil, groundwater, and phosphorous as practically unlimited resources we abuse and discard all too readily. We kill our bug populations indiscriminately, etc. On, say, Mars they will need to be very thoughtful and careful about every single one of those things. They'll need to treat their resources as the precious and limited things they actually are. Which is true of here too (we're draining our aquifers like there's no tomorrow, but there is a tomorrow). Those habitats will drive development of technologies and solutions which will be incredibly valuable here on Earth as well, and may help drive us toward a more mature relationship with our environment and our use of resources.