Any use for Sceptile?

Yeah it’s a great grass mon and you’ve already got the ideal move set.

If Omastar returns as a raid boss...

I assume 13 is the attack?

On borderline Pokémon like Sceptile I usually for their niche (which in this case is double grass - and would have bulletseed as fast attack). I think it’s worth having an attacking Pokémon with the three bar charge move. Now you may have venusaur(s) with Frenzy plant which in some ways replaces it in that role. I have 2 of each maxed out - but only powered up a second Sceptile because I hatched a perfect one. As is - regarding attacks - it is a good gym Pokémon and less vulnerable.

Yes, a great grass attacker.

Also it is 13/10/14, 11 defense IV isn't correct.

Even if you have a couple FP Venusaurs on your team, I doubt you have 6. Sceptile is fantastic in the first slot of a Grass team and great for swiftly clearing out mid to low motivation gyms

It's an exceptionally good attcker fpr gyms, both as a grass and as a generalist (thanks to this moveset^).
It s great in raids too, if grass weakness...

I would say don't power it up, it is outclassed by FP venusaur, and is on par with eggy, when gen 4 is released it will be outclassed by leafeon, rosarade and tangrowth l, by your candy supply it won't be a good budget grass mon, and grass is only optimal in situations where there is a double weakness, which currently no bosses have, so I would save the dust

FC/LB Sceptile is a great leadoff mon for a grassy team. Full stop. It's fun to use, too, if enjoying yourself is one of the reasons you play the game.