Deconstructing the conversation to highlight what Benoit Blanc noticed
Linda: Yes, I mean, Walt, he's done well with what Dad gave him. But really, Dad hands him a book twice a year and Walt publishes it. It's just not the same.
Linda very clearly thinks less of Walt's achievements, and argues Walt is being helped.
Linda: Not that it matters.
Linda is attempting to pretend that she's merely stating facts and not revealing her feeling about Walt. However, given her multiple statements that deflate Walt's achievements, this attempt is a really thin veil.
Benoit: But surely Walt runs the merchandising, adaptations, film and television rights,
Benoit intentionally inflates Walt's status after he notices Linda deflating it. He knows Linda disagreed and he's intentionally trying to spark a debate.
Benoit: I mean...
I'm singling this line out because of its efficacy. Benoit uses this to hint that he's going to rail into a longer conclusion about Walt's great achievements.
Linda is too attached to her own self-worth to even entertain the conversation in which Walt is an equal to her. Benoit knows it and is doing his very best to make points that Linda disagrees with vehemently enough that she'll speak.
Linda: Are you baiting me, Detective?
However; Linda is also not an idiot, and self-aware enough to know that (a) she doesn't think highly of Walt and (b) Benoit is blatantly countering what she just said. It's the eloquent equivalent of "yes he is!".
In essence, Linda draws from the conversation exactly what I wrote in this answer, and therefore figures out that Benoit must intentionally be baiting her into a conversation.
This is then comically subverted by cutting to Richard who spills the precise beans that Benoit could not get Linda to spill.