Ich finde, "anspringen" hat eine zumindest leicht negative Konnotation; ich denke da an "ködern" als Synonym.

Kann man "what they can bait their customers with" sagen?

fall for ?

... falls das nicht vor vornherein zu negativ wertend ist ... nur dass es wohl im Endeffekt daraus hinausläuft ...

I think "What their customers will fall for" is probably too negative: at least, it definitely sounds like the customers are being somehow misled.

You could use "leap at", but that is so strongly tied to "offer" that you'd probably want to reformulate: how to make an offer their customers will leap at...

I think the "bait" suggestion would work too, but I think "lure" is the word more commonly used in that context -

"knows what will lure in their customers."

Wie wäre es mit „what triggers the customers‘ interest“?

"piques interest"?

BTWDIK ;-)

I would prefer BLZ Bubb's "pique" to "trigger" (BLZ makes me think of BLTs, guess it must be lunchtime.)

But I think both are two passive for worauf "anspringen"

BTW, to me, both of those sound slightly off in the present simple in this sentence (can't really say why, there is just something too perfective-ish about the meaning of verb...)

With them I would use the future: what will pique their customers' interest.