If I draw from what Dr Gary Chapman mentioned in his seminal book "The 5 Love Languages, Quality time is not just about being there with your child. It is also about taking interest in your children's activities, and also involving them in your activities.
Parents I worked with have espoused doing the household chores together with your children, enforcing a team effort in ensuring the house is clean. Some parents decry the benefits of spending exclusive one to one time with each of their children. Regular quality time allows you to connect with your children, and would also allow you to bring up sensitive issues such as your child's behaviour in school within a more secure context with your child. Your child may not be comfortable around a mother or father who only comes in to tackle problems when they occur. On the other hand, having regular quality time sessions with your child would set the precedence for you to bring up a fighting incident that your child's school teacher had alerted you to.
Ultimately for me, just do more of it if it works. If it ain't broke don't fix it. If it doesn't work, it's time to try something new!