i dont think it'll botteneck anything. loading games into RAM would be faster but i mean u wouldn't notice a difference in gaming really.
other uses would be say u have that iso with winrar, if u were to extract the iso, the 4gb would be a matter of seconds to be extracted rather than a minute or two with a hard drive. any ssd is good for "common use cases"
the bottleneck of ur usb would be the usb port not being able to transfer fast enough to the usb, but that is irrelevant to a ssd.