Alcohol-based leather dyes penetrate the leather deeply, so the color goes beyond the surface. The colors are usually vibrant. However, after the dye is applied and the alcohol dries, it takes some of the moisture out of the leather along with it.
Leathers dyed with alcohol-based types when then usually benefit from application of a leather conditioner to restore some of that pliability and the oils within the piece. Often, dyed leathers are coated with a finishing coat, to seal in the dye, prevent it from rubbing off, and protect the leather overall.