The phrase often implies genuine admiration rather than polite flattery. John has a lot of time for his mentor, owing to the honest guidance he's received.
Pro Tip 2/3
Personal Value
It reflects the speaker's personal opinion, not a universal truth. Emma may not be well-known, but I have a lot of time for her ideas.
Pro Tip 3/3
Not Literal
It doesn't mean having free time; it's about having respect or admiration. I have a lot of time for volunteers; they make a real difference.