Here is my take on it. Ultrasounds can be life saving. They also can be life wrecking. It depends. You just have to use your brain. You can't just follow your doctors orders willy nilly, you have to think about why you are doing it, what benefit it's going to provide to you and make your decision.
In my opinion, there has to be an indication. So, whatever the condition the patient is in or has, if the fundal height is normal for the week, the baby is moving well, the mother is feeling well, the heartbeat is good, blood pressure, protein, etc are all good, why should she have to get regular ultrasounds - even if you are old, black, white, on high blood pressure meds, diabetic, etc, etc. etc.. It's stupid.
For example, If you have high blood pressure, and everything is good up to that point, maybe you would opt to do the anatomy scan at 20 weeks to ensure your placenta function is fine and the baby is growing properly (which you already know). If that's fine, then leave it at that unless there is another indicator suggesting another look may be necessary. Without indication, it's stupid - and that's where I feel ultrasounds are overused and the information abused, used incorrectly to force women into unnecessary and often very costly interventions.
The big business of genetics is also a very big question of mine, but it's like filtering though a huge abyss that I didn't want to go through.
The best way to make decisions is to educate yourself. Knowledge is power.
In my opinion, if it makes you feel better (aka not worry) than that's enough reason for me, you know? If I was going to worry day and night that there may be something wrong - it's dumb. Just get the ultrasound and get on with your life, kwim? The baby feels your stress and anxiety - which in the end could be infinitely worse.
Meditation during pregnancy is essential in my opinion. Perhaps prayer.