I've had two occasions recently where I knit the same stitch patterns from charts and from written text. I've had a preference for charts for a long time. Working through both pattern formats taught me exactly why. I made many more knitting errors when working from the text version. I noticed that when I made a knitting error using text I often had to tear back 3 rows to find where I went wrong. When I was using a chart I would go back to the beginning of the current row, turn the work and read the stitches back from the chart. Using charts I caught every error in the next row not several rows later. When using text, instructions like "knit to the next marker" often allowed me to miss an error, total stitch counts help but sometimes one error will offset a second and the count will be right but the knitting is wrong. However on a chart the stitches are laid out so you can do a section by section count and verification between markers even when the counts vary from one row to the next. When using charts, markers that slip under a yarn over are immediately both obvious and fixable, when using text you don't know there is a problem until the next row doesn't work correctly. Charts also allow you to think through the knitting in a vertical way. The stitches relate to the ones in previous rows whereas text forces you to work horizontally and view stitches only in relationship to their neighbours on each side. I've always noticed that I memorize a stitch pattern much faster when using charts and I often create one when I use a stitch dictionary that has text only. If I still haven't convinced you I assisted many knitters in my LYS when I worked there and I noticed that only the knitters who use text stitch patterns struggle with maintaining stitch patterns during shaping decreases and increases. Knitters who use charts never need the same amount of help to learn this skill.
If you don't already use charts and don't want to take the time to learn to do so; just think about how much knitting time and frustration you might save yourself if you do.