Getting published is also a time consuming process. Peer-reviewed journals are considered better than non but can take months for a manuscript to get through the review process. A journal with a quicker turn-around may not have as high of an impact factor, possibly due to more lax or no review process, but could get your results out to the world faster, leading to people citing you sooner. Meaning, for the right study, the benefits from publishing in a mid-tier journal with a quicker turn-around could outweigh the benefits of publishing in a top-tier journal. So, when publishing, a scientist has to weigh the pros and cons of quantity, quality and timing.
New scientists who don't have any publications (as a first-author or otherwise, like me), typically go for the lower tier journals for their first publications to get their foot in the door. Lower tier journals are also a good place to publish a smaller study that may not hold a lot of clout on its own. The other option is to aim high and hope for the best. Worst that can happen is your publication isn't accepted for review and you go a little lower. It might take a little more time but if you get into the higher tier journal, your "little" study could create some waves. This was the route I took.
Yesterday, I submitted my first manuscript for publication to a journal with an impact factor > 8. I have my fingers crossed that it will get through to review. I've gotten good feedback on it pre-submission and, although it's just a subset of a larger study, the results are significant (to know exactly what that means, you'll have to wait to find for when it actually gets published, which could take weeks... or months! I'll keep you posted).