I dunno if it'll work with Sigrok (now or ever) as it's not on the compatibility list, so I hope the proprietary Chinese software won't be too awful...
As for 500MHz, that's beyond wishful thinking. Sure, you can sample a slow signal super fast (which is quite pointless), but that design with totally inadequate "dupont"-based probes (high inductance/high capacitance, coupled with super ghetto grabbers and all -- which is perfectly adequate for a $5 Logic8 clone) isn't gonna get close to sampling signals
anywhere near this fast... If anything it'll just interfere with the signal integrity to the point of making those fast signals stop working. It should be able to do around 60MHz or so (perhaps 75). It doesn't appear much better than a $35 Logic16 clone (but almost as expensive as the real thing), sorry
I don't think you are correct. Keep in mind a 500MHz sample rate is really only suitable for maybe 50MHz asynchronous digital signals if you want to have ANY reasonable timing fidelity in the samples.
Granted at 50MHz crappy probes will start causing some poorer signal shape but it's perfectly reasonable to use and be effective.
For instance the Lecroy logic analyzers are 500MHz sample rates, they use what you indicate as "crappy" probes and it works just fine. I doubt lecroy would sell a tool, sample rate, and probes that were essentially worthless as you indicate.