Broadband or Leased line?

Can anyone please explain the difference between a business leased line and broadband to me?

I’ve got a situation in my residential building right now (around 50 different flats) where we’re in talks with Hyperoptic (broadband provider in U.K.). The Original plan was that they would build in fibre to the building and each individual flat would have the option of getting their own dedicated home Broadband service from Hyperoptic if they choose to. However, that appears to have changed now, and they’re building in a business leased line for the whole building to share. Is there any difference in the services here? Is a leased line less secure and more contended if being shared by multiple flats? Or is it the better choice in this situation?

Any help would be appreciated!