They did fit the scene. Z was a continuation of Dragon Ball, so naturally it used similar music, sometime with a sci-fi edge or insert songs with techno in them (like Solid State Scouter for the Bardock special).
Here's a comparison from last night
Goku's speech JPN - https://www.youtube.com/watch?v=arr_hU-iGB8
Notice how quiet it is for the first bit, with the only sound being character's talking and background noise from the environment. Then, a theme in the background builds up along with Goku's speech, and it's meant to make Goku's transformation look and sound divine, given the peaceful nature of the song.
Now, we have the Faulconer version - https://www.youtube.com/watch?v=fmfyp_4JpUE
There is music constantly playing from the start that doesn't fit the story or the landscape. It sounds techno, and actually, when I hear it, I think of Biohazard 1.5, a fucking Resident Evil beta.
This theme never builds up, it stays at a constant low and it just doesn't fit the scene at all.
We could also compare another scene, but the one I'd compare, Gohan's SS2 transformation, would be just unfair, as the Faulconer tracks could never beat Unmei no Hi
I'll leave it on this clip here, comparing the music and VAs in the Bardock special, and the dub butchers the whole thing.https://www.youtube.com/watch?v=qqn_bXKH4nI