Just as Mr. Li improves the draw action, The Supplier improves the install action. More notably, he lets you host costly cards on him, lessening the burden on your grip. The lesser cards you hold, the more you can draw up on cards you need now.
In terms of pure value, his ability seems to be a Criminal version of ": Gain 2" with some caveats. However, since you don't spend another click to install, it also saves you that click. The way I look at him is ": Install a resource/hardware and gain 2." Now that's a lot of value, obviously with some restrictions:
- Only works on resource and hardware, preferably 2-4.
- Once per turn, delayed install.
- You don't actually gain 2.
Just remember never to host Political Operative on him.