Are Internships Important for MBA Admissions and Placements?

I'm preparing for CAT and I'm confused about whether I should focus entirely on CAT preparation or spend time doing an internship as well.
My profile is average academically, and my main goal is to get into a good MBA college. Are internships really important for MBA admissions and final placements, or is it better to dedicate all my time to CAT preparation?
For those who got into top MBA colleges, what would you recommend:
1. Focus only on CAT and aim for the highest possible percentile?
2. Do an internship alongside CAT preparation?
3. How much do internships help during MBA interviews and placements?
Would love to hear your experiences and advice.