Fairly sure they mistyped, and "engineers" should be "designers". Otherwise that is indeed a very confusing statement.
There's usually multiple developers/engineers for every designer on a team, so bringing them in to the product with features that require full privileges would certainly be a lucrative move for Figma.
>>karate+(OP)
Yup, I meant to say there are more engineers than designers. Figma was great because we didn't have to worry about seat count cost for engineers.