Until now the Sky Store was only available to Sky TV customers, or those using the NOW TV service. The movie rental service has now been opened up to anyone, meaning you can rent content ahead of it appearing on most streaming services.
The popularity of OTT services such as Netflix and Lovefilm Instant has been the large libraries of content for a fixed price, but other services such as Blinkbox and wuaki.tv have ran a hybrid system for sometime, i.e. digital rentals and subscription based services.
Whether the market is willing to pay £3.49 to rent a movie for 48 hours is a bit of an unknown though one assume plenty of people are happy to spend this as Google Play and iTunes also charge similar amounts. Most excitement and demand has been for the £5 to £6 unlimited streaming services, but the annoying rights system means that studios hold back films for extended periods making rental or purchase of physical media the only option.
The future is likely to be exclusive deals with certain studios releasing films ahead of general streaming release, and everyone having to suffer several rental apps on their TV or media console/device. Integrated searching is the real key to getting people to use the online services, as it is time consuming to search multiple stores to find a specific film or who has the best price on a specific day.