The Adobe Experience Platform Web Software Development Kit (SDK) functions on the client side using JavaScript. If you're exploring the AEP Web SDK extension and already have a Data Collection/Launch property set up, you can proceed with the implementation within the same Property, depending on your use case.
In comparison to Adobe Analytics, which utilizes the appmeasurement.js library through the Adobe Analytics extension in Data Collection tags (Adobe Launch), the Web SDK appears more streamlined. The Web SDK uses the alloy.js library, combining various Adobe technologies into a single JavaScript file.
While Adobe Analytics requires the deployment of two extensions (Analytics and Experience Cloud ID Service), the Web SDK simplifies this to just one. The Web SDK implementation involves defining the XDM schema for standardized data collection and configuring the Datastream to instruct the Adobe Edge server for data transmission to Adobe Analytics.
In summary, the Web SDK offers a more unified approach with a single network request to adobedc.net, whereas Adobe Analytics involves two extensions and separate network requests to demdex.net and omtrdc.net for ECID and Analytics, respectively.