The amount of misinformation in quora answers is absurd. Dude was seriously trying to tell me let is slower than var after I provided him data proving that they are nearly same in performance tests.

Also, #javascript-problems

Somebody is wrong on the internet!
stop everything, we got to fix this!

Haha. Fair. Although, quora seems to be getting treated as a new stack overflow like site and it's a lot less reviewed and isn't held to the same standard. Then again stackoverflow was probably a bit too strict.

I would love to see that conversation on Stack Over where the conversation would be closed within 10 sec and the poor guy would write a new question asking why that happened which would again be closed!!

Ohh wait, I've already seen that...

Let me tell you a story

It's easy: modern features are better for self documenting code and bug reductions.
Your production code can be transpiled and you get the best of both worlds, if var is faster than let/const, and you can support more users.

But yeah, quora has some sketchy answers, to say the least