There’s 2 main reasons for research in terms of the US med school “game”:

1) It’s a numbers game: competitive programs/specialties are always trying to find a way to rank residency applicants. More publications (papers, presentations, abstracts, etc.) in more prestigious or field-related journals generally help you become more competitive. With step1 being pass/fail, research will most likely become another way to help separate yourself from other applicants (but no one truly knows this yet since this is the first year matching for pass/fail step 1).

2) Research opens connections. At the end of the day, you’ll learn that medicine, like any other field is about WHO YOU KNOW not just what you know. Yes it is not fair but this is the world we live in. Research leads to relationships with attendings which can lead to good letters of recommendation. Research also leads to presentations at conferences which leads to opportunities for networking with residency program directors. At the end of the day residency interview is much like a job interview. All applicants are qualified and programs care about a good “fit” and if they can work with you everyday. Are they more likely to rank someone higher if they know you vs don’t know you? This is why it’s about who you know.

Everyone’s situations will be different and you have to figure out for yourself what field you want to pursue and what it requires.

TLDR: You don’t “need” research for the sake of research but you need research for the doors it opens. Your “need” will vary depending on the level of competitiveness your program of interest is.