A lot depends on the project, but ...
Everyone likes when the leaflet is colorful, aesthetic and legible. However, a lot depends on the project itself, in other words, graphics preparing the files for printing. He must be aware of the basic matters regarding composition and layout. A well-made leaflet will certainly have a better effect than a short, ugly one.
A lot also depends on the printing house and the selection of paper and the type of printing. A leaflet looks better on shiny and smooth paper than on a torn parchment. The type of paint and the method of printing is also not insignificant, and its selection is best entrusted to a specialist in this topic or to pass on a printing company that has extensive experience with each type of orders.
Standards in print and not only
Standards in every industry and business are important. Imagine that we buy a monitor and its input does not match our video card, even though it has the same type. That's why certain standards apply.
In polygraphy and graphics, such standards also exist - appropriate definitions of CMYK colors - key for the appropriate color reproduction. Specified in advance formats for printing leaflets and business cards, so that they are comfortable and as uniform as possible. Without standards, even leaflets could be completely unreadable and even repulsive.
We print, print!
The printing era has been pretty good since Gutenberg. First, important things were printed like books. But these are REALLY important, not some literature for the mob. Well, because the mob was quite illiterate at the time. Then also such fiction was printed, meaning for the reading of the book. Well, since the last 50 years (even hundreds of them), it's all about printing - books, leaflets, business cards, even shirts, mugs, pens ... Well, really everything. Because you need to build brand awareness at the customer, i.e. printing and marketing is an inseparable couple. Because you can print everything on your T-shirt and have it originally. Well, who would prohibit the rich?