Changing mags "with retention" would be a bit silly in real life
In all seriousness, the "D" in IDPA stands for "Defensive" as much as the "P" in IPSC stands for "Practical". They're sports, not tactical defense training to handle real life scenarios.
That being said, I think any shooting sport that counts for speed and accuracy will make you a better shooter and these skills could certainly be transferred to defensive situations. In other words, you could protect yourself better if you know how to use a handgun really well than if you didn't.