This might help you understand here;
Wood studs used in light-frame wall construction may require horizontally-oriented blocking for a number of reasons—including blocking at shear panel edges, fire blocking, and buckling restraint when subject to axial loads.
This is an area that apparently various AHJ’s do differently. I’m interested in leaning what variety is out there.
The code for my area is pretty clear that the mineral wool insulation counts as the fireblocking, and the mid blocking might be about stud twisting but is not a fire requirement at least for less than 10 foot ceilings:
CRC 2019 R302.11 Fireblocking
Fireblocking shall be provided in wood-framed construction in the following locations:
In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs, as follows:
1.1. Vertically at the ceiling and floor levels.
1.2. Horizontally at intervals not exceeding 10 feet (3048 mm).
At interconnections between concealed vertical and horizontal spaces such as occur at soffits, drop ceilings and cove ceilings.
At openings around vents, pipes, ducts, cables and wires at ceiling and floor level
R302.11.1.1 Batts or Blankets of Mineral or Glass Fiber
Batts or blankets of mineral or glass fiber or other approved nonrigid materials shall be permitted for compliance with the 10-foot (3048 mm) horizontal fireblocking in walls constructed using parallel rows of studs or staggered studs.