Macbook VS Airport Express

[HarCees]

I have a 2009 Macbook white for spare that I use as a wifi-hotspot/router. Im currently on 802.11.n (My Imac G5 is on 802.11.g tough, don't support anything else)
I do not have any computer that supports the AC-technology and therefore Airport Extreme is out of question (..or is it?)

Anyway, as my apartment is small I have always planned to buy an Airport Express but then it hit me; Isn't the technology inside the airport express the same that is inside my Macbook? Apple calls whatever is inside my macbook for "Airport Extreme"(not confusing at all).
Why should I buy an Airport Express when Airport Extreme is already built into my computer?
Have I missed something?
Will I get a better wifi?
What is the possible benefits?

I can't say that my current wifi is super, but I am worried an Airport Express won't do anything better than my current Macbook does.

Thank you for your time

 

[COrocket]

For one, the airport express will consume less power, which can eventually add up for a device that is usually powered on 24/7 (although laptops are pretty efficient - so it might not pay for itself in electricity savings) and it would take up less space.

It is hard to make an apples to apples comparison between wireless sharing on a macbook and the express since the radios/chips are not the same. I'd imagine the express would give better reception since it is purpose built as a router. If you are only using the iMac with 802.11g wireless than it may not make any difference. What internet speed do you have and what are the results when you test the connection with something like http://www.speedtest.net/ ?