Could be...
By reducing the CL on CB card, SBI could achieve the following:
1) Obviously reducing the proportion of risk exposure to the retail credit market and utilising this same share to acquire the new market in the form of the possible exodus of Axis CC customers as result of their recent devaluation... I doubt there could be that much exodus from Axis anway.. May be SBI is looking at this differently to me.
2) Even if people like me want to make big purchases beyond CL to get CB by prepaying the amount, the SBI is at a gain, beacuse they are getting money upfront and there is no need to wait for 50 days and better cashflows hence less costs...
3) SBI Cards is itself a very peculiar organisation whose business is solely issuing credit cards... Normally Bankers along with their normal banking business segments issue the cards as part of their one of their revenue streams. So a normal bank can recover the lost revenue(if any) in CC business from other activities and still report +ve results. Where as SBI Cards have to earn their income only thru Cards business and hence these tactics by SBI cards IMHO.