You're asking two separate questions of a type more suited to the discussion forums. The first is, "Will this USB 2.0 thingamajingy work in my laptop computer?" Almost certainly it will, if your computer is new enough to have USB 2.0 ports. An advantage of wi-fi via USB rather than a card is that you can avoid mechanical issues and locate the adapter/antenna in a better place for reception using a short extension cord, e.g. the dashboard.
The second is, "Can I get wi-fi in the field?" The answer is, "Yes."
However, you must be clear on what wi-fi is and is not. 802.11 ("Wi-Fi") is a short-range communications standard designed to cover distances of a few hundred feet or less. Practically speaking, one must be stationary near to an access point in order to use it; and one must be granted access by the owner of the access point. Using an access point for which one has not been granted access is illegal.
What constitutes "granting access" is somewhat controversial and way above my pay grade and expertise. But if access is limited to so-called "open" access points (broadcast SSID and no encryption) and if the access is limited and not for illegal purposes, then you're in the realm most chasers use when they use wi-fi in the field. It's now quite easy with newer access point devices and adapters to configure encryption, so leaving an access point open is very plausibly construed as the owner's decision to grant access.
A few years ago one could cruise the main street of a small town and find multiple open access points of residents and businesses. This is less the case now with the newer devices and media attention to wi-fi security issues. The best sources are motels, eating establishments that want to attract wi-fi customers, and public facilities such as libraries. My Verizon aircard had a large data hole in northwest Oklahoma, so I personally used open wi-fi on the road several times last year -- once on a Sunday afternoon courtesy of a bank
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An important and continuing use of wi-fi is night and morning at the motel. Those connections are sometimes faster than aircards and don't draw down limited data plans.
