There is an invitation to other bus operators and EMT to come on board. They would have fallen foul of the Competition Commission if they hadn't given all bus operators an equal opportunity to participate. Presumably the others declined for the time being, perhaps on the grounds of not having suitable readers, or too few routes within the area to make it worth their while.
To me this is a missed opportunity. Day travel is capped at £3.15 per operator and £4 total, so good value for regular but not daily Kangaroo users (surely can't be many people?). But the NCT pink Easyrider card is still much cheaper per day if bought in lots of 100 days, so the conundrum remains of which option to use in the morning if you don't know whose bus you will be coming home on in the evening.
If you're using an Easyrider enough to make 100 days worth loading you'd probably be better off with one of there green ones.
The weekly capping will be the interesting one for people like me - i.e. use the bus occasionally, can make do with one operator but having the choice of multiple ones is very beneficial (i.e. getting the next bus home after an evening out as opposed to waiting for 40 minutes), occasionally have spurts of higher use (e.g. when off work for a few days) but can't really afford to top up a pink Easyrider up with enough days to make it worthwhile, and seeing the Kangaroo as being overly expensive. Also handy of the days where we are planning to go out after work - where you've got to choose between paying for a daily ticket you might not use (i.e. when it's late and you get a taxi home), or paying over the odds for two singles
I think the next few years will be interesting here - i.e. when the weekly capping is introduced, when travel cards can be loaded on, if the D2N2 stuff sees it rolled out across the wider East Midlands, and if it's extended, like Oyster, to simply work with contactless cards.
Think of say three years time - when the City Card, Mango, Easy Rider are retired and all the regular season tickets / 10 trip Mango's are on the same card.
You add your regular NCT Monthly East Rider ticket to it and use this most days and you PAYG.
Or you have a Kangaroo on your Robin Hood for day to day use, then decide to spend the day in Derby and use it for PAYG over there, and your train journey back.
Also, as it's an ITSO compliant card hopefully all the countries operators will have got their act together and delivered on the promises - i.e. your NCT Anytime Monthly Ticket and EMT Nottingham to Leicester Season ticket will be on the same card, and then you decide to visit Brum and add a Plus Bus ticket to it and the same card works for your Cross Country Trains service to Brum, and then on Local buses once there. Alas, sods law dictates I'll still have a Robin Hood, City Card, Oyster, and Stagecoach Smart...