It's a remarkably low spec device, and anything that's not fairly well optimized is going to behave poorly (games show this constantly). Node.js (V8) was optimized for use on servers and general purpose computers with multiple gigs of RAM and absurd levels of processing power.

So, yes, I think that using Javascript on a low spec device is probably a source of slowness.

It likely is being used server side. I seriously doubt Node is being used on device

I hope so as well. Still honked off about the performance of the store though.