They usually provide the cheapest flower delivery because you are cutting out the middle men, like Interflora, etc.

They can also advise on which flowers are in season or readily available. In season flowers are cheaper than ordering out of season flowers.

Also, since you are talking directly to the florist you can ensure that your loved one receives that something extra, like a personal message directly from you.

Many florist today also carry a small range of jewellery, which would also complement the bouquet.