Though I hated 0870 numbers dialing from a mobile perspective and this site has helped a lot to circumvent by using 01/02/03/.
Since the last 2-3 years I must say 0870 access numbers were a blessing and it did save me £100s if not £1000s!! - a lot of money using my virginline which had 0870 included in the package.
For e.g a 40 min daily call to India would otherwise cost £20 (with talk international or the using cheapest calling provider card/app etc
) - saves at least around £20 per month!. Beauty of it was smartcall app that made it work when abroad - so the savings compounded!
I really hope it comes back and hope someone publishes a new working 0870 access number soon
...
From a business perspective - I think there is still revenue to me made from it seeing the connection charges (roughly 11p, though I don't understand the business of access numbers.