True. However, you cannot really compare a simple single-task single-user single-input iOS device to a full-fledged personal computer running macOS. Macs are infinitely more complex than iPhones and iPads, and have a plethora of possibilities at their disposal to corrupt data on-the-fly. Think power failures in the middle of a cached write. Think crashes while in standby with open file handles. Think file locking due to competing simultaneously running background processes accessing the same inode. Think multi-user multi-tasking multi-processing versus single-user single-tasking multi-processing. Think sandboxing and jail versus open access. It's just not that simple, and while it's true that APFS on iOS has been rock solid so far this doesn't necessarily mean that APFS on macOS is (or will be).
Like you said yourself: 2.5 years is a very young age for a filesystem. Coming from the UNIX and enterprise Linux world I personally consider a filesystem somewhat solid after maybe 5-10 years of widespread use. APFS may seem structurally sound and solid but it simply hasn't been around long enough yet to make any assumptions. Call me old-fashioned and paranoid, but I've been around long enough to see my share of "whoops, that wasn't supposed to happen" on oh-so-amazing greatest-invention-since-sliced-bread filesystems. Once bitten, twice shy