I'm with Lee D on this.
A few years ago, I wouldn't have been. Those who disagree with him, your points are perfectly valid, BUT consider this.
It's a service the Supermarkets have have introduced, and are actively pushing (both online shopping and click-and-collect). The logic is unfathomable, as click-and-collect they are doing your shopping for free (and reducing store footfall, plus a reduction in upsales and impulse purchasing, but hey-ho).
It is a *huge* convenience. As Lee D doesn't quite put it, it's a genuine time-saving service. For a fiver (or £4 using Tesco), you can save a couple of hours less the time on-line shop).
It's environmentally friendly, and reduces road traffic. Replace 5-10 shoppers in cars with one small van
For some of us, who moved to a city and SOLD our car because of a) congestion b) higher insurance c)higher fuel costs due to urban motoring/slow moving and stationary traffic and actually made use of bicycles to commute rather than a car, and why pay insurance, VED, MOT, servicing costs on a depreciating asset which is used for shopping and the once-a-year trip South, online shopping is a necessity for the 'weekly' shop with large bulky items such as 17Kg bags of dog food, 16 toilet rolls, potatoes, etc.
So the once-glib answer of "walk and do it yourself" isn't quite so valid anymore.