When I started eating chia seeds in my morning oatmeal, one of the biggest things I noticed is how satiating my breakfast was. I was full well until lunchtime, at least two and a half to three hours without needed a midmorning snack. This helped with digestion because I find when I eat too often or too much, I always get bloated.
As far as my overall digestion, I didn't feel like eating chia seeds had a huge impact. I already eat a high-fibre diet rich in veggies, legumes, whole grains, and fruit, and the extra 1.3 grams of fibre a day wasn't adding a ton more. I will say that my mother started adding chia seeds to her oatmeal after she heard I was doing it, and she said it greatly improved her regularity — everyone is different!