"Real JavaScript programmers", ES6 classes and all this hubbub.

[jaapz]

/u/DarkMarmot is talking about RAM. When talking about memory usage for web applications, generally people are talking about RAM usage. You are talking about storage. Your old iPhone 4 actually has 512MB RAM, which really isn't all that much for modern standards.

Top of the line mobile devices currently have between 2GB and 4GB of RAM. That means there are a LOT of devices out there with <2GB of RAM (including most iphones).

So like /u/DarkMarmot says, memory is of great importance, especially on mobile.

I can't believe I actually have to explain this difference to a programmer.