Careful, there is two different things going on here:

a) whether you use the maybe-entropy provided by the CPU (and/or the bootloader)

b) whether you credit that maybe-entropy towards your tracking of whether the pool should be considered sufficiently seeded

random.trust_cpu/random.trust_bootloader configures b).

nordrand has been removed from the kernel as it had become overloaded by meaning both a) and b)

Under most circumstances, a) is harmless. You mostly want that off when the CPU exhibits some performance hiccups when asked.

Under some circumstances, b) is outright dangerous. Some applications can work without seeded pool at some slightly reduced performance, but could be made to fail miserably if they had been made to believe that the pool was seeded yet it was not. This happens with hash tables when you skip some of the accounting because it seems no longer relevant. It really would not be relevant, once even a determined attacker should be unable to reliably trigger the worst-case-performance.