Generally, with a modest application on a high-performance platform, you're going to use X (maybe 2) servers for redundancy purposes only. While this is indeed

Generally, with a modest application on a high-performance platform, you're going to use X (maybe 2) servers for redundancy purposes only. While this is indeed more complicated than a single server, it's still significantly less complicated than many modest-application architectures I've seen on low-performance platforms. Low-performance platforms tend to find themselves in significantly more complicated architectural territory including sharding work, job queues and workers, clusters of micro-services, a grab-bag of other technologies bolted on in "best fit for the job" fashion, varieties of caching, and so on. A single load balancer with two identical app servers each of which handle thousands of users is really simple by comparison. You might even have them in cold-failover. But like I said, what performance means to you is a subjective thing. I personally strongly prefer a high performance ceiling, especially since I can have that while still enjoying a very developer-friendly experience with many modern platforms. There's nothing wrong with big hardware and complex architectures, when you need them, but I'd prefer keeping things simple for modest applications.