There actually is a limited situation where this could be useful. Someone who has a really old 3DS or 3DSXL, but updated it past 4.5 using a cart. If you updated it past 4.5 but not past 9.2, your system is vulnerable to exploits, but since cart updates don't contain the browser, you might not be able to use the browser exploit. I've seen at least three separate instances of posters who really did have this problem.
Which means you could load a borrowed Sky3DS with OOT and the Gateway hacked save, use it to run Gateway once, and downgrade to 4.5, at which point you can give the Sky3DS back and use a Gateway from then on.