Function Of The British Post And Go Stamps

These have been around for nearly a decade but I am puzzled. What function do they have which is not already covered by ordinary postage stamps and stamp booklets available from machines?

Reduce queues, make some money from stamp collectors ... The usual stuff.

https://blog.postofficeshop.co.uk/post-go/

Hi GeoffHa,
I have always suspected that this is the case! But in what way does it even reduce queues if stamp booklets can be bought from machines outside the post office? At least that used to be possible; since I haven't lived in the UK for a long time perhaps that isn't so any more! Please enlighten me!!!

Stamp machines outside post offices are a thing of the distant past in the UK. There are more than 55,000 outlets (newsagents etc) that now sell stamps in addition to post offices, so why go to the trouble of managing machines seems to have been the reasoning behind stopping booklet vending. Fully printed coil stamps also stopped for similar reasons. Post and Go offers far more choice in the way of services than the old type machines and only require a software change when postage rates change. It is a great product, ruined only by the sheer proliferation of collectable types. This has now settled down and is rapidly becoming a postal product, rather than philatelic.