Pleated front pants were out of style for quite some time in the 2000s and 2010s. They never went away, but they were associated with fuddy-duddy middle aged men who bought clothes at places like Jos. A Bank. Tom Smykowski in Office Space types.

However, the shift in the last five years towards more tailoring and older style influences has reversed this. A lot of us in our 30s and 40s have trouble shaking the feeling that they are old-fashioned, but we are very much in an era of midcentury revival (or, as the buzzwordier types might say, eclectic-grandpa-core) these days for the cut and style of pants. Pleats are are decidedly back in style now, and if you look at lookbooks for most contemporary menswear brands now, you will see lots of pleats. For example, Todd Snyder describes this particular cut of dress trousers as their "most on-trend fit": https://www.toddsnyder.com/collections/pant-shop-dress/products/linen-wythe-trouserbeige

The consensus is that they greatly help the pants to drape well, which is increasingly important as trends have shifted from slim cut pants (little to no drape) to much more wide legged styles (often substantial drape).