How is Adobe Lightroom from Creative Cloud different from the Microsoft store version? Basically nothing. By deciding to buy it, you will be offered exactly the same functionalities. What's more, people who download Lightroom from Microsoft Store can take advantage of the 7-day free trial period. Of course, if you currently have a Lightroom subscription, you can also use it for the version of the program from the Microsoft Store.
In all this is a small catch, but really tiny. Well, basically two. Lightroom from Microsoft Store needs Windows 10 with 1903 (May) or newer to work properly. Given that it is already December, and Microsoft some time ago released a widely available patch 1909, this requirement should not be a problem for many people. The second requirement is a minimum of 4 GB of RAM in a computer, but I assume that people using graphics processing programs have 8 or more gigabytes of RAM in their computers long ago.