The military offers many cash bonuses. There is the sign on, airborne, specials forces and many more depending on the mos chosen. There is also the GI Bill. Which can pay for most if not all of your college after you are out. Or if you're in the reserves, you can do schooling while in the reserves. Not using the GI Bill yourself is an option as well. It is possible to give that money to a spouse or children for their college.
If you are single, housing is free in the barracks. The barracks are different for each branch. Off base living is an option but it is not paid for. If you were married, living in the barracks is still an option. But living on base in a house with your family is more ideal probably. Living off base is somewhat paid for as well if married.
Traveling around the world is another benefit. Discounts from movie tickets to cars is also quite possible.
There are many options when it comes to jobs. It is not just infantry and mechanics. There are desk jobs that can qualify you for government jobs after service. Employers like experience over someone who has only a degree with no experience. If you have a clearanced job you are guaranteed a job in that field over a college grad.
The list can go on and on about why the military is better than college after high school.
For some people it's better because it gives them opportunities that they would not be able to have without going to the military (free college, a job, healthcare), but for most it's just a hindrance. For me, it would waste my time because I know that anything military related is not what I want to do with my life and being in the military would not give me any experience related in the field I would like to go into (chemistry).
Also, when I'm in college I will most likely be able to get an internship related to my field in a company that I like that I would not be able to find in the military. I also did very well academically in high school, so I don't have to pay much for college.
In all it would be best for me to go directly to college because being in the military would only slow down the process of me getting a good job.