I have tried this before on my wallet app, but it just displayed a blank image. Though I didn't have any money inside. I also tried on another one and it gave a notification that this action is not allowed. I don't know but I feel like this feature will not stop some stubborn people. Since their phone will not screenshot, they will just use another phone and snap the screen. And it is only going to be their fault if they steal their money.
Yes Some wallets will stop you from taking the screenshot of your seed phrase due to the dangers of it while others will actually warn you about the dangers and still allow you to take the screenshot afterwards. In both cases I just feel the wallets are actually giving you extra precautions and this features to me doesn’t make any wallet more secure than one another. I am reading from some replies that wallets that allow you to take screenshots are not secure and I don’t think so. Even if they warn off some users, some would still write it down and then take a picture of it.