Can an architect actually build a house?
I believe that in California an architect is licensed to build non engineered structures as well: Structures that do not require an engineering contractor to build. This category includes most infrastructure such as underground utilities, bridges, dams, roadways, power plants and other similar structures. So technically speaking at least in California an architect is licensed to build a house. Mind you, being licensed and being actually capable are two different things. Construction requires a different set of skills than design and engineering.
The Bauhaus in prewar Germany required its designers to be crafts people as well. Mies Van de Rohe was a brickmason as well as being one of the great architects of the 20th Century. However, not all architectural programs require their students to be familiar with or skilled in any of the construction crafts.
Depends how good the architect is at laying bricks.
Architects design, and builders build. Architects need to have an idea of how all elements and materials junction/perform etc to allow the builder to build what's proposed.
You will find that insurers don't cover labour as part of an architects scope of works. In the UK at least, you are unable to practice without insurance.
A separate policy would be required to cover any physical building works.
May b no