I started quilting in the late 70s before the rotary revolution and although I've tried to the side, I've almost always pressed open. I came from garment sewing and it made sense to me. For the most part, early quilting books and patterns didn't discuss seams very often, not on the pressing or even the size.
I am a big believer in pressing my seams open and have my reasons for it, biggest is for me it makes them much more accurate. I like having "one rule" instead press to the dark except here and here and there and that....I believe that pressing to the side is an artifact (leftover rule) of hand sewing and that with sewing machines and irons and well woven fabric is just not necessary nor ideal.
There are times, however, such as with curves and some other specific reasons when I will press to the side.
Yes, you have to learn how to press correctly, it isn't that hard nor that time consuming. Keeping the chain sewing together helps align the seams and makes it much faster and easier than doing stacks of single connections.