SCOTUS is undoubtedly more important a position than DC Circuit. I wouldn't disagree at all that she thinks that this high-profile, decades-of-precedent-setting position is worth the risk/challenges in her life and that the DC Circuit position wasn't. I don't see why that's supposed to be unreasonable or damage her. Coming out this way means she's going to be dragged through the mud publicly for a bit and, more likely than not, harassed for the rest of her life. Calculating when it's worth it to bring that on yourself with public accusations isn't nefarious.
Like bmags said, this position for Kavanaugh is very high-profile and he'll be in the public for decades to come if confirmed. I don't think any of us could name the rest of the DC Circuit judges beyond Kavanaugh or Garland. Now that Richard Posner's retired, I couldn't tell you the names of any of the 7th Circuit judges that cover Illinois. Yes, these are still important positions, especially the DC one, but SCOTUS is that much more important.
Many, if not most, sexual assaults go unreported. That doesn't make them "unimportant." This was important enough that she sought therapy for it and it's stuck with her for decades. Making the decision on when to make a public accusation doesn't speak to the importance of the crime of sexual assault, it speaks to what our society puts accusers through.