As has been said, they’re pliers, just with parallel jaws.
Currently, they’re widely used in smaller sizes in the jewelry trade.
In the larger 6-1/2” and 8” sizes (with cutters, which is a standard variety) they’re used as one of the standard fencing pliers in Australia.
The 6-1/2” size, and maybe the 8” size, both have Nato Stock Number designations, since they’ve been used in certain Military tool kits since WWI. (Signal Corps and Armorer’s Tool Kits used the pliers)
There are Stainless and rust free coated versions made for surgical and orthodontic use.
Originally, the pliers were also marketed to Ophthalmologists.
After WWII, they were also heavily marketed as fishermen’s pliers.
Sargent Tools is the successor of the William Schollhorn Co., which made arrangements with the original inventor William Bernard, to be the official manufacturer of the pliers. (Bernard became part owner and a salesman and inventor for the Schollhorn Co. ).
The original design was patented in 1890.