Comment by garganzol

JS runtimes are fatty, so embedding one instantly adds at least 30-50 Mb of RAM usage. Imagine that you do this for just for a specific function (JSON processing) and your total RAM budget for a whole pod is around 256 Mb.

No doubt, this approach would work reasonably well for machines with plenty of RAM, but I can see why it can be a bottleneck when scaled to N instances. RAM is expensive, and when you multiply those 50 extra megabytes by N, your total costs quickly climb up.