I purchased a valve index back when they restocked in march and as soon as I got it delivered later that month (thankfully I got into the first wave) I instantly bought some lenses from vr optician. It just wasn't comfortable for me for long sessions, not to mention that my current glasses didn't even fit so I had to use my old glasses with older prescription. The pressure on the sides of my head would start to cause pain after around 1 hour. Once the prescription lenses arrived, it was a life changer.
1. I was able to adjust the lenses as close to my face as it would go so max FOV.
2. No more pain from clamping the glasses frame.
3. I now have a built in protector for the delicate lenses. I would much rather replace some £90 lenses than a whole £500 headset .
I went for the Zeiss blueprotect coating. I'm not sure what the difference is as I have not got an uncoated set to compare but it's nice to know that my eyes are at least a little more protected I guess.
All in all, yes. 100% worth it. I will never go another day without lenses for my headset.