What would be use of Neck exercise (excluding treps muscle), does it look good visually or does it help in lifting? I don't see any utility in training them.
I can answer this. One day when you're my age, you'll turn your head at work to talk to a co-worker and you'll feel a pop in your neck. You'll go numb on the left side of your face, have shoulder, chest and arm pain, and suffer with mobility issues for months.
Only after months and months of physical therapy will you be able to turn your head again. All this because the stabilizer muscles in my neck had to support my crap posture using phones, computers and other bad positions my entire life.
Your head is somewhere between 12-20 pounds. It's the job of your neck muscles to support and hold the head. If you have poor posture like 99% of modern people, you'll slowly start wearing away at those muscles. Don't end up like me. Treat your neck well and do exercises to strengthen them!!