The o2 website is a store like any other digital store. I did not find a unique feature in o2 (except for a 2-character domain, of course).
Products from Apple, Samsung, Google, Sony and several other brands are listed in this store. I did not see many offers in the store, and of course, considering the possibility of buying in installments, their profit percentage is commendable.
Apart from the smartphone segment, Apple and Samsung watches also have a lot of variety in o2, which has made this store a relatively complete store in terms of product inventory. Of course, as I said before, these are all general features, and in the competition of online stores, the most special ones are always selected by users with unique offers.
It seems that most of the activity of this store is virtual and only one address of their office in the UK can be found on the website.