The short answer is that no seller wants to hold a note and needs a good reason to do it. A good company in a competitive market will have numerous offers and if there are 2 similar offers, one with a note and one without, then the seller will take the one without the note. However it's a good idea to have one if you can negotiate it because then the seller has some skin in the game. It's easiest to negotiate as a bridge to a valuation gap or to mitigate a specific risk (e.g. customer concentration). In these cases it's a good idea to make the note contingent on hitting milestones the seller has claimed will happen.

Typically there is a portion of seller financing in various capacities in every deal. Overall I do not advise my clients to provide more than 10% in seller financing. Overall there are many ways to skin the cat but your offer has to entice the seller in other ways (ie price/terms) or you most likely will lose out on many deals.