Danielle explains this clearly in the article. Mattermark "couldn’t raise a traditional Series A on acceptable terms."
"I quickly discovered expectations for a B2B Series A were $1.5M in annual revenue run rate — we were growing fast, but still only 1/3 of the way there at the time."
They don't have enough revenue so they went for another seed round instead. It's not questionable; it's logical and helped her to keep the company moving forward.
No board seats
Not a lot of money raised, so not as dilutive as typical Series A
No expectation to hit "Series B" type metrics next time they raise