Doubles can represent integers exactly up to 2^52

At least historically integer operations also offered lower latency and higher throughput on CPUs. For decades integer addition and bitwise logical operations have been the canonical single-cycle instructions that any microarchitecture could perform at least once per cycle without visible latency while floating point operations and integer multiplication had multi-cycle latency if it was even fully pipelined.

Zen 5 breaks several performance "conventions" e.g. AMD went directly from one to three complex scalar integer units (multiplication, PDEP/PEXT, etc.).

Intel effectively has two vector pipelines and the shortest instruction latency is a single cycle while Zen 5 has four pipelines with a two cycle minimum latency. That's a *very* different optimisation target (aim for eight instead of two independent instructions in flight) for low level SIMD code going forward despite an identical instruction set.