Some addresses are not clearly good or clearly bad. They sit in the gray area where confidence is lower and the right answer depends on your workflow.
That is especially true when catch-all behavior is involved.
Three practical options
1. Keep them and monitor
This works when bounce tolerance is reasonable and the segment otherwise looks strong.
2. Segment them separately
This is often the safest middle ground. You keep the audience, but treat it differently from your highest-confidence segment.
3. Remove them in higher-risk workflows
If the list is being used for cold outreach or another low-tolerance send, conservative removal can make more sense.
The key principle
Do not pretend uncertain addresses are certain.
The right decision is the one that matches the risk of the campaign, not the one that makes the list look largest.