Pensioners should have 100% of their retirement funds in equities

[Dr Strangelove]

in a bond fund will leave them open to daily fluctuations in value and an uncertain income that depends on that fluctuating value.

Indeed think this is a bigger issue for DB schemes.

More generally bond markets are more susceptible to regime shifts via central bank policy. Bond prices hang together tightly while equity indices are by contrast a collection of often idiosyncratic businesses.

Risks of different types exist in both products.