Here's an example of why bridge repeats aern't optimal for training FTP, which as pointed out you need for long climbs.
That's my file for the Mt Accosta Endurance Classic, 3 hours of Bridge repeats.
It was a heck of a workout, I burnt 75 matches (the number of times above FTP) But if you look at max 10 and 20 minute power, I'm well below FTP.
It trains the wrong things for sustained climbs.
So some bridge repeats will be helpful, but not at expense of working on your FTP.