I'd ask a slightly different set of questions: (1) "Is it good for {country} if {country's corrupt leaders} are able to bank elsewhere?" (2) "Is it good for {bank elsewhere country} if they accept corrupt money?"
(1) is probably not good for that country, but do other countries care? To some extent, this is just colonialism by proxy: extracting wealthy inequitably from a foreign country. Historically, few third party countries take issue with that, when they're the winners.
(2) is where the more interesting point is. Does the country accepting the money net benefit, or net loss? Aka the London banking question in a nutshell.
I'd argue that if money is political power (it is) and corrupt money can't be firewalled (it can't), then it's net loss.
Inevitably and especially if we're talking lifestyle roots (e.g. property, establishing a home, etc), that corrupt money corrodes government and civil systems in the banking country. At minimum, because the wealthy corrupt people bring their expectations and behavior with them!
