Smith's only really strength as a half has been accelration and using that running game on a retreating or staggered line, which Sam does better anyway due to the added ball playing and football iq.
I think the kicking is the obvious part for Savala where Sam has a gap, and takes some contact away from Sam. Plus a bigger bodied half stops the issues of previous seasons needing to give cover to both sides of the ruck.
Smith can definitely be the back up 9 questionis more long term fitting him and Watson (who play extremely similar).
On goal kicking Sam kicked at the same clip as Nathan Cleary last year on conversions and only 2% below sandon.