- Only useful when actually being used, which is never the case. (Seriously, can we make at least ASAN the default?)
- Often costly to always turn them on (e.g. MSAN).
- Often requires restructuring or redesign to get the most out of them (especially fuzzing).
Rust's memory safety guarantee does not suffer from first two points, and the third point is largely amortized into the language learning cost.
Android helps a bit into that sense,