I suspect, in the long-run, the 'patents' may be what are intrinsically so valuable to SPT, think royalties, or, with the size of the 'market', think how much a large, well-funded competitor would pay to corner the market...
Not sure if VISA and M/Card can actually legitimately challenge them (ironically, because the patents essentially protect a vulnerability in the existing payment processes and infrastructure-platforms globally)...
As I understand it, SPT patented 'business-processes' are simply a 'loophole' that VISA and other payment providers haven't realsed existed (until now) as essentially, business-process 'hacks', or in 'cyberspeak', exploitable vulnerabilities in their operating-models...
The problem might just well be SPT's ability to 'fund' the massive litigation if other 'providers' essentially look to exploit this loophole, using the SPT 'patented' loophole... Remember the Apple vs Samsung 'tablet-design' saga that ended in a 'massive, undisclosed' settlement between the parties...
Happy to be challenged or proven wrong by those more intrinsically aware of the SPT engine, but, as I understand it, that, at a high level,, is where SPT is at atm... It's a 'risk-play' but either way, it's very disruptive to the 'well-established' industry-players...