As a designer of a minimalist deck (The Orbifold Tarot), I can speak to some of the reasons why a creator might do one, and what at least my intent behind minimalism is, and some of the challenges faced by minimalist designers.
First, minimalist art in general is not necessarily faster than more complex art, in planning, design, or production. Minimalism is about refining an idea to its essence, so that even complex ideas can be communicated simply and clearly, while still containing depth and nuance — this is no easy task!
Speaking from experience, although my deck was relatively quick to design initially, its simplicity proved to also be the one of the very same things that caused production (post-design!) to take nearly 9 months.
With very few elements to communicate with, those elements and their accuracy and precision become EXTREMELY important — that minimalism is far less forgiving than when there are more elements to the design. Everything has to be "just so" and a change of half a mm here, or colour saturation there makes all the difference. Designs with more going on in them have their challenges too, I am usually doing more illustrative art, but these can also be a little more forgiving in some ways.
For the Orbifold, my main intent was in creating something that digs under the tarot structure and reveals its blueprint. It was not about limiting tarot to a few key words (although I do find doing so to be a useful part of the process in both design and reading), it was about opening up the themes in such a way that readers are not "stuck" with one depiction of a particular theme — the abstraction, mixed with the essence of name, gives the reader much more freedom.
For beginners, I do understand how this could seem too obscure to understand, intimidating even. I remember I certainly was intimidated by pip decks early on, and I WANTED PICTURES to tell me what the card meanings were so I wouldn't have to keep referring back to the books.
But eventually, I learned that the tarot structure is, at its base, very simple — if you can observe where threes occur in life, in cracks in the sidewalks, in how branches and certain flowers grow, in how groups of people or animals behave when there are three of them, how we delineate things into triads, how we use threes in language and repetition, and then do the same for all numbers from one to ten, then you can understand ANY tarot number.
Then, relate to each of the elements: Fire can be an easy one, so investigate where heat and light show themselves in life, in our language, in our interactions and descriptions of things... then pair that with your number and voilà! You have all the minors.
So in many ways, an abstract or minimal deck can be the best place to start for a beginner because you will understand tarot's STRUCTURE rather than relying on the pictures, and viewing them as 78 images that seem at first to be unrelated.
I'm not saying one is better than the other, I love my image-heavy decks too, but these are some of the advantages I see in minimalist decks, and a start at explaining what inspired me to create one