I think its best use is harvesting berries. It is basically the midgame trike, although i like the trike more with combat. The stego has a slow attack, but is has a large hitrange, and so it harvests lots of berries at once. It also has a decent carrying capacity. I suggest to upgrade weight and melee.
If you don’t want to run around gathering fiber and wood to quickly build a base last moment before the Allosaurus pack nearby spots you, if you want to tame Argies quickly and effectively, if you want to take out raptor packs quickly, you will need a stegosaurus.