I see 8 visitor parking spaces in your picture. Quite a few houses will likely have more than 2 cars. Some couples have 3 cars just between them without kids as they will have 2 cars and a van. Now think of all the visitors and people that come round said housing estate. Now think of all the houses that have kids that drive as well. Now think of the selfish people that will park in the visitor spots permanently to leave their driveway free for when they or their guests want to come round and park on the drive.
Basically as already pointed out, those spaces will be permanently filled/used/hogged/abused because that's what people do on estates. There is NEVER enough parking on any new build estates, even with houses with double drives and garages. You might get unlucky and get someone who likes to permanently leave their long wheel based, dirty, great big white van there, sit in it whilst chatting on the bluetooth with the speakers turned right up resonating around the estate.
Saying the above, it's not like they are right outside your window. You could grow a hedge to block the view. Also, you could use the spaces yourself so it might come in handy if you ever have a household with 3+ cars. Or if you want to be that guy, you could park your cars in them permanently. This is where it is important to check the rules on their usage.