I never really thought of it that way. Admittedly the F-8A had similar performance (better in some ways, possibly a little slower at top-end) and was used in this capacity.
That appears to be similar for the F-104, though I'm curious to what extent it (the F-104A/C) was used in defending NATO nations from bomber-attack
This is something I have seen before - the claim that the F-8A was, like the F-100, barely supersonic. This is not correct.
The F-8A (F8U-1) had a top speed of 1,013 mph (M1.53) at 35,000 ft. This was the slowest of all F-8s, and the F-8B (F8U-1E) was similar..
The F-8C (F8U-2) had a top speed of 1,105 mph (M1.67) at 35,000 ft.
The F-8D (F8U-2N) had a top speed of 1,228 mph (M1.86) at 35,000 ft. This was a "limited all-weather/night capability" fighter, and the fastest of all F-8s.
The F-8E (F8U-2NE) had a top speed of 1,133 mph (M1.72) at 35,000 ft. This was a fully all-weather/night capable fighter.
The F-100A had a top speed of 852 mph (M1.29) at 35,000 ft.
The F-100C had a top speed of 924 mph (M1.4) at 35,000 ft. This was the fastest of all F-100s, and still significantly slower than the slowest F-8.
The F-100D had a top speed of 864 mph (M1.3) at 36,000 ft.
The F-100F had a top speed of 852 mph (M1.29) at 35,000 ft.
The XF8U-3 and F-100B (F-107) are different stories, of course.