There is a difference between 'Yes, this is working and playable" and "Wow, this is really immersive and feels like I'm actually here" in VR.
I know this to be true based on my experiences with my own two existing HMDs (Vive and Rift) and 2+ years of using them while upgrading my PC along the way.
Sure, I can play stuff at 45-65, and It doesn't make me sick but it's not the same as playing the exact same game at 90FPS.
The complete lack of frame jumps and fluid head motion of 90FPS vs lower FPS makes a difference in VR. Lower FPS is VR makes me feel like Im enjoying a computer game in VR, while high-end FPS make me feel like the vision through the HMD is actually just my vision.
I loved playing VR for a good 5 months, raved about it anywhere I could, it worked great... Then I upgraded my PC and realized everything I was missing. Take out frame drops and glitches, and it's almost another thing all together.
To each their own, but if you've had a chance to try VR and then also try it on a competent VR PC, you'll know what I'm talking about. Low FPS wont ruin a game, always, but if you're trying to immerse into Elite or a sim - Low FPS will constantly remind you you're playing a game