1-Always Good To Have A Buffer Between You and The Seller:
They can be a conduit to help deliver bad news to the seller. There may be instances where you have to retract or modify an offer and certainly times where you'll need to adopt an aggressive negotiating position. Since you'll most likely need the seller to train you after the purchase, it's not a good idea to aggravate them too severely. As such, let the business broker deliver the bad news.