The higher sample rate is useful, because it effectively gives higher precision when finding the zero crossings; however, you could reduce the .wfm size by sampling at 50 GS/s on the scope then upsampling on the computer.
That would be better. Upsampling on a scope is dangerous, it's just too easy to fool yourself about what you're really seeing. Much better to use a slightly more clever algorithm on the PC than just "nearest crossing".
We tested the 5 Series predecessor to your 6 Series and I was amazed to see 10 or so volts on a 3.3V logic signal... until I remembered to check the interpolation setting. There was, in fact, no measurement above 3.3V (ok, within the usual tolerances) but the dumb shit machine had made things up and displayed them as if they were real. Even though they would have meant there was a serious hardware fault (not impossible, it was a new design going through bringup and there were in fact higher voltages on the board!), nope, it was the fault finding tool that was faulty.
I've had zero interest in the 5 Series since that demo week. Terrifying machine. (And it was supposed to have been "debugged" by that time.)
(Also, the probe itself has a max bandwidth of 10 GHz, so it will filter those frequencies before they're sampled by the oscilloscope)