I have a friend who flew one and was stationed at the Fulda Gap. He said that should there ever be an attack he was told to expect a 75 to 85% causality Rate.
But... the depleted Uranium 50 caliber bullets were awesome. I think the sacrificial “low and slow” nature of the weapon bothered people.
The Fulda Gap is or was in East Germany - no US troops were in that area as it was held by over 300,000 Russian troops - the closest any US forces were based was 4KM from the border; casualty rate, once the Russian mechanized Armies passed through the Gap, would approach 100% since tactical nukes would have been deployed already. Some strategic once also (limited to theater). Depleted Uranium rounds had not been invented at that time. Once past the Gap it would be about 72 hours before the Russians reached the Channel. That was how it was from 1950-1973.
Helicopter life expectancy was 15 seconds. A-10s would have been a few seconds longer had they existed at the time (the first ones flew in 1974). The US did not have the forces then to stop the Russian advance. After the fall of the wall 1989, the unification of Germany, and the fall of the Soviet Union in 1991, the Russian forces were withdrawn and the US had achieved a measure of technological advantage over a no longer existing enemy.
By that time 1974, there was no longer any real danger of attack which had passed years before.
Your friend in the A-10 could not have entered the Fulda Gap area until after 1989. By that time the A-10 was a plane without a mission.
FYI: 20mm, not .50 Cal.