Considering it's below 1000 feet, losing GPS could indicate an "unstablized" approach and require a go-around, as opposed to losing it at a higher altitude where the pilot could have more time to safely switch to alternatives (other navigating aids or go to visual?).
Source: my guess after watching a lot of aviation YouTube videos......
For anybody who doesn't know, a "stabilized approach" is an approach with a constant angle and speed as the plane descends and lands. This allows the plane to keep consistent control settings (flaps, throttle, etc).
It's best practice/policy for all major airlines to use stabilized approaches and most/all require a go-around if the stabilized approach is interrupted (there are edge cases and exceptions).
Source: my guess after watching a lot of aviation YouTube videos......