Due to the nature of probability, spread can theoretically make you miss all your shots in one engagement, and hit all in an identical next engagement.
Not quite true. If the engagement happens close enough (target covered entirely by minspread cone, maxspread cone, or somewhere in-between) some (or all!) shots are guaranteed to hit. This is without recoil of course, add recoil and you get even more ambiguity but the principle still holds.
Another nuance of the spread model is pacing or bursting. You can make your engagements way more consistent by slowing down your firing. Other times the ease and risk of longer bursts is worth it.
Overall the spread model has more nuances than a pure btk-model. With spread there are more factors to consider and learn (higher skill, IMO) than no spread, where the answer is always "hold down the trigger".