Search partners come up in almost every account review, and I still don't see a clean consensus. The argument for switching them off is that the clicks come from sites you don't control and the placement reporting is thin. The argument for keeping them on is that they can add volume without you adding keywords.
For a lead gen account on a tight budget, I'd start with them off. A few weak partner clicks can eat money that Smart Bidding would otherwise spend on your core terms. Say a dental clinic spends $300 a day: if the partner segment shows real cost and almost no calls or form fills, that settles it. But I wouldn't decide from clicks alone. Check conversions and cost per conversion by network before changing anything.