I always called it a "kick-stand" ... on my previous Yamaha & my current 1150, I've got a metal tab that rotates into place and prevents the motor from dropping any further.
With the Yamaha, I did what V153 suggested ... flipped the tab down, trimmed it down tight, disconnected battery and away I went.
With the height of the 115, I see the center of gravity being much higher. Despite the "kick-stand," I can imagine that trailering would result in the motor wanting to rock forward (trim up direction) away from the tab. I can't imagine a transom saver would hurt & it was probably developed as a solution to a weak/flexible transom intended to generate a slightly longer lifespan out of something that was already failing. ??
In my current case, the best transom saver would not have prevented the problem of a half-way job done on replacing the transom by the PO. I've got solid wood, but no structural support for it.