this is similar to Kasina meditation, one of the oldest concentration practices in the Buddhism. You focus on one of 10 subjects including Earth, Water, Air, Fire (elements), Blue, Red, Yellow, White (colours) and Space, Lights. These subjects can be found anywhere and most importantly neutral so you won't or unlikely to have sensual attachments and association. This is considered an entry to mediation. It's easier than focusing breathing because breathing is movement and very natural so you're likely to lose focus. The biggest advantage of breathing to 10 entry subjects of Kasina meditation is it's everywhere. Effort or single-mindedness or focus is one of 8 noble paths in Buddhism. And meditation is to improve focus/concentration. At least that one of the purposes of meditation.

Edit for grammar