I’ve used Vocalign/Revoice a lot. True, It’s often (but not always) more accurate than Cubase Audio Alignment, but it’s also quite a bit slower and faffier to set up, using insert effects and side chains, and it doesn’t give perfect results every time either. (You say 98% of the time, lucky you I’d say! I only get about 75-80% success on a first attempt and it’s a lot slower to get there!) The Cubase Audio Alignment is so very quick to use that I’m now always trying it as a first option. If I can’t get the result I want, I just Ctrl+Z then try Vocalign to see if the results are any better. Vocalign and Revoice have more processing controls but again thiese take time to set up and try. (similarly for vocal tuning and simple alignment Variaudio is useful to to me because it’s so quick and embeded into Cubase. Melodyne and Revoice may be more fully featured but it’s slower more complex workflow.)
In my experience, for both Audio Alignment and Vocalign/Revoice the clarity of the of the clips you’re processing seems critical. For vocals, breaths and conflicting dynamics + annunciation can properly mess things up with either system. It pays to clean up the audio rigourously for breaths, ambient noises, mouth clicks, etc before processing. Also, the length of the clip seems to matter - I usually chop things up into small parts first.
I agree, Audio Alignment could do with some refinement, but IMO it’s a good start . Even as it is right now, It’s so quick to try that there’s barely any reason not to. Going back to the Variaudio analagy, the first Variaudio outing was pretty basic but nowadays with all the quick controls right on the audio, it’s very slick to use for monophonic parts. Hopefully Audio Alignment will mature similarly