Define 'need'. In college I learned, besides all the normal CS stuff:
* writing
* accounting
* organizational psychology
* small amounts of business stuff
* lots of EE, digital and analog
* how to read and write research papers
* how to research
* how to prove theorems (important if you are inventing your own)
* linear algebra, calculus, stats and probability, discrete algebra
* physics I-III, plus 1 semester of experimental physics
* chemistry (I,II, no organic)
* a bit of philosophy
* circuit design
* numerical computation
It would be a Herculean task to take all that up in your spare time to the level I did at school (I still learn on my own time, so you have to catch up not just with what I did at school, but everything afterwards). It's 4+ years of opportunity to bump against really good minds. I went to professors and said "I want to learn x". (think of the course catalog as a suggestion!) That got me, among other things a co-authorship with a professor on an academic book. All of that has been relevant to my career except for the chemistry. Even with that, my first job could have used it if I had stuck around more, and it is useful to know if you want to be scientifically literate.
Or, you know, you can punch your time cards, do the bare minimum, and graduate with a pretty useless certificate.
College as voc tech to learn to manipulate the LAMP stack is probably a poor choice of time. If you want to be able to take a job to compute cancer statistics, program robots, build digital interface cards, perform computer vision, simulate the ocean, write aircraft wing simulations, model and research traffic flow, work on medical devices, you almost certainly need more then votech and/or self learning, IMO. I've done most in that list professionally, and friends of mine have done the rest (no rockets in that list, but I was offered a job to do that, turned it down).
There are multiple paths to life, but the chance to just think and learn for awhile is pretty incredible if you can afford it.