Micro optimizations are important, and their importance is described by a LWN posting about the linux kernel:
Most users are unlikely to notice any amazing speed improvements resulting from these changes. But they are an important part of the ongoing effort to optimize the kernel’s behavior wherever possible; a long list of changes like this is the reason why Linux performs as well as it does.
And is not specific for the Linux kernel, but you can apply the same strategy to every piece of software. AEM as a complex (and admittedly, it can sometimes be really slow) beast applies the very same.
There are a number of cases in AEM, where do you operate not only single objcets (pages, assets, resources, nodes), but apply the same operation on multiple of these objects.