The wall above has to go somewhere
Upper floors, roof loads and masonry that used to bear on the old wall need a new load path. Depending on width and available side supports, that may require a beam, posts or a steel frame.
Temporary works are part of the job
The existing structure needs safe support while masonry is removed and steels are installed. The sequence should be agreed rather than improvised once the opening is cut.
Beam depth affects the room
A deeper beam may project below the ceiling. Hiding it within a floor zone can be possible, but this usually affects joists, services and cost.