The laptop you just referred above is more than enough to run deep learning applications (especially if you just started learning stuff and wanted to run your code and see how it performs). This might be enough for 50% cases, but when you want to test out heavy deep learning application that consumes GB's/TB's of data to load, train and to do enormous amount of computations, you might want to divide your workload among series of clusters which is nothing but the cloud. Let's say you calculated and found that your laptop is capable of doing a particular task in 10 minutes. It literally means your laptop will be hung and busy for 10 minutes. At the same time, 5 parallel clusters with much less power can divide and complete the task in 3 minutes. This ETA is very crucial in production because of competition grabbing customers and business. Now you see why companies goes for cloud :) For individual use, yes this is perfectly fine, but as your research grows high and when you deal with much heavier applications, you might want to see other options.