The Keighley service isn’t an Asda free bus, it’s a public service K8 that runs to Asda
However it is indirectly paid for by ASDA - it's the result of Section 106 charges on the development.
Originally it wasn't too bad, being an extension on the 719. However, when the frequency of the route dropped from 4bph to 3bph it ran as a separate service. It serves 3 stops, including both termini. Keighley Bus Station, Keighley Rail Station and "ASDA". However the stop at ASDA is so far from the store that it's usually easier to catch it just one stop and use the side entrance to ASDA. As well as the 3bph on this route, the 662 runs at least 6bph with 2bph on the 60 which stops just across the road. It doesn't start until 0905, with a last journey at 1405. On Saturdays it runs until 1605, missing out buses at 1245 and 1305. It's usually run with a double decker, despite very few passengers using it.
http://www.keighleybus.co.uk/cmsUploads/route/files/K8WEBtimetableJuly2017-2.pdf
The Sainsbury's bus in Halifax is a better kept secret. It runs from the bus station to Sainsbury's, serving nowhere else. The timetable is not on the Metro website and the number of the bus is not on the operator's website. There's a timetable at the stop which is about as far from the entrance to the supermarket as it could be whilst still being on their property.
https://bustimes.org/services/c68-sainsburys-halifax-circular
Oh, yes. Sainsbury's is almost next to the bus station. Google maps reckons it's a 5 minute walk, but it doesn't direct you by the shortest route. The bus takes 4 minutes.