This particular workaround is a very tiny risk for a careful person and certainly nothing that can't be easily undone.
As far as updates go, I cannot answer that question since I haven't had to go through that experience yet. It's not a major job though so if it needs to be redone, so be it.
It's a fact that the Apple Truetype version of Helvetica can wreak havoc on documents that were created with Postscript fonts and very few designers want to
have to go through a multipage document fixing everything.
Then there's the problem of those who are unaware of the issue who load Postscript fonts along with the Truetype System version and encounter difficulties at print time.
Apple's engineers made a mistake when they made such widely used fonts as Helvetica and Helvetica Neue a part of the required System font library. They really should undo their mistake in a future version of the OS.
If they had gone the whole nine yards and included every style of those two families as part of the System font library that would have been acceptable to me, but they didn't. As a designer, I need the entire family available in a common format.
So I need to fix it and the risk is very, very small that something will go wrong.