You need both at depth. strace and dtruss translate binary information to a textual representation but they’re only as good as their coverage. When you get closer to the edges of common use they fall down. On macOS / iOS using dtruss for all programs comes with extra burdens, too.
We (tailscalar here!) have another post out today on more throughput optimizations and the story there is related in this way: when we started working on that code path the docs didn’t exist! (There are some docs now, in Linux). But either way the stuff is seldom used outside of specialist implementations - so when you need to understand what’s going on you’re headed for the source, or a debugger, or a symbolic tracer rather than an interpretive one.