Let me offer a slightly different perspective.

Compliance is a very big field. It ranges from financial reporting to tech risk all the way to anti-money laundering. It is true that an MAS officer will not have experience in all of these fields (unless he has rotated around the various departments). Indeed, it is also rare even for people outside MAS to be able to specialize in so many areas.

Where an MAS officer can add value, is how they are able to grasp the regulations, even of departments different to their own. The fact of the matter is that MAS is a very principle-based regulator. Our regulations are thinner compared to other jurisdictions that have 99 rules for each of their 999 regulations. Being able to understand the broadly what the regulations intend for and then further drilling down into the hard requirements is something that a company would also want.

No one can say for certain whether an MAS officer (or for that matter, any other candidate) would be a good fit for a company. However, it is a fairly common occurrence to find MAS officers making the transition into the private sector, some even in senior roles. To a large extent, the labour market for certain compliance roles is tight that may also be contributing to this; FIs may well be more accepting of less than ideal candidates as long as they have some regulatory/compliance experience.

Of course, if you are talking about making a switch from a compliance role to a rates trader in an investment bank, then yes, that would be quite a feat.