My opinion is that the body benefits from tight ab muscles. Many old-time (pre steroid) body-builders had great abs which they often trained 5-or-6 times a week (traing but not over-training). Unlike most skeletal muscles, the abs can take several consecutive days of light-to-moderate training without ill effects.
You could also train different parts on different days (dividing frontal movements, side-to-side movements, & twisting movements) if you wish.
There are some simple very-old Chinese breathing exercises which exercise the abs quite well while you just stand & breath -- it's called "5-Animal Play" (WUQIN QIGONG; consiting of 5 postures: Ape, Deer, Tiger, Bear, & Bird; Ape works the low-abs; Deer works the upper-abs; Tiger works to stretch the lats & also hits both the front-abs & the obliques; Bear works the obliques; & Bird works the centerline of the back) & it is well-described & photographed on pages 41-thru-44 of a book titled "THE WONDERS OF QIGONG: A Chinese Exercise for Fitness, Health & Longetivity" © 1985, ISBN 0-935099-07-7 (if out of print, then it's worth searching for if you want the benefits of tight abs without doing the more common western ab exercises).
Hope this helps you decide -- remember it's your body: what you do or don't do will affect you 1st & foremost.
Take Care,
Marooned Mike