Depending on the genetic predisposition, people may store fat in different places in their bodies.
The place people refer to as the "lower belly” is complained about most in the first place. It is pointless to do thousands of sit-ups to destroy these fat cells.
For example, in one study, the participants were given abdominal muscle training 6 days a week for 5 weeks. At the end of this process, no change was observed in abdominal fat volumes.
As a result, the videos titled "2 moves that take away the lower belly" or "Get rid of the lower belly in 1 week" that we see a lot on Instagram and Youtube pages are just a hoax.
The chances of doing the movements you see in these videos in the right form on your own are low and you are more likely to injure yourself.
The movements you see are not the product of your sports history, or your injury history, in short, these are not a program prepared for you.

Even if you do the movements in the most correct form, another significant danger is that these programs are not complementary and do not work the agonist and antagonist muscles correctly.
For example, if you constantly follow a program consisting of only abdominal exercises so that your "lower belly" area runs, unless you do work on areas such as hips, waist and back, you may see postural deteriorations after a while such as kyphotic posture as a result of the tightening and shortening of your abdominal muscles.

As a result: even if you exercise your abs as much as you want, your abdominal muscles will not become more visible unless you create a regular and stable calorie deficit. Abdominal exercises can strengthen your abs and add a small amount of volume to your muscles. however, a calorie deficit is essential for the abs to become visible and to get rid of your "lower belly".
You can support this calorie deficit with your workouts, but at the end of the day, the famous saying will remain true: "abs are made in the kitchen."
The common opinion about the amount of fat which is required for the abdominal muscles to become visible; People with 18% or less fat in women and 14% or less in men will have more prominent muscles.

The core of our body connects the lower and upper extremities.
Therefore, we get support from our core area in all kinds of physical activities we do, and the abdominal muscles are important parts of the core area.
If we consider a professional football player, he gets support from the core when he jumps to hit the ball and he takes a hard shot.
Whether you are a sedentary individual or a professional athlete, strong abdominal muscles, I mean,
A strong core area will enable you to do any physical activity more comfortably and effectively.
Therefore, it is important to strengthen the abdominal muscles with the right programme.

NOTE: Sports science is a constantly evolving field. As of 29 December 2022, as a result of current research and my personal experience, here are my views.
As new experiments are conducted and new research results are published, the opposite of what is written here can be claimed.