Not being an expert, having a problem, learning, and overcoming the problem is the narrative circle.

Walking in as the foremost expert on everything is called a Mary Sue and is correctly derided as bad writing.

If we had been introduced to Pulaski being a virologist and then in later episodes her expertise is useful, that’s fine, narratively.

Edited:

Picard travels to the best heart surgeon in the Federation. Billions of humans. The best out of Billion:

"PHYSIOLOGIST: You’re unwilling to make the attempt??

SURGEON: I’m not qualified.

PHYSIOLOGIST: I know someone who is."

<Pulaski>

Best virologists in the Federation (again that means billions of people) doing cutting edge research:

"KINGSLEY [on viewscreen]: To whom am I speaking, please?

PULASKI: I’m Doctor Pulaski, Chief Medical Officer.

KINGSLEY [on viewscreen]: Katherine Pulaski, author of Linear Models of Viral Propagation?"

It’s hamfisted writing.