It's surprising to see how little people mention Adyen in this thread. One of the big benefits of Adyen is that they also supports many more payment options besides credit cards. For example: Paypal, iDeal, Card Blue & SOFORT Überweisung. If you're serious about receiving payments from consumers in Europe, supporting these is pretty much a necessity.
If anything the icons would make it more suitable for "heavy use" because once you get used to them they are an improvement to the old text, defeating the point of this superficial article even more.
The most important thing when learning design is to learn and use the right process. Except for the very abstract inspiration part, everything listed here would all fit in the last 50% of my process as an 'educated designer'. I believe there's much more low hanging fruit in the first 50%. It's hard to give concrete examples for this though because it's all very dependent on the kind of product you aim to design.