The core idea is simple and intuitive: buy a company substantially lower than its intrinsic value.
Broadly speaking, it is hard to argue against the idea of margin of safety. It is how investors approach the margin of safety that can wildly differ.
But isn't changing the discount rate to estimate downside essentially a bet on exogenous macro variables (e.g. interest rates, risk premiums etc)?
I approach margin of safety purely from company specific fundamentals perspective.
The more narrow and more precise predictions required, the lesser the margin of safety.
The very essence of margin of safety is the future is unknowable and hence unpredictable which is why we would like some buffer. A resilient balance sheet provides exactly that.
For most long-only long-term investors, it's not the batting average, but the slugging ratio that makes all the difference.