This is exactly a setting where rules would be better than discretion, in particular to avoid the time-inconsistency problem, highlighted in the work of Nobel laureates Finn Kydland and Edward Prescott in 1970s and early 1980s.
Kydland and Prescott (1977) consider the implication that people, including investors, could look into the future and anticipate the behavior of self-interested governments, so that a discretionary monetary policy could end up being compromised by government pressures, leaving inflationary expectations unanchored, whereas a monetary policy committed to a rule would be harder to bend and keep inflationary expectations at bay.