If a scroll/wand/talisman has a spell in it that is level 30, does that mean you are casting it as a level thirty user, or that the spell if it lands will land as level 30 spell, or both?

In other words if I'm 51 and I zap you with a level 35 curse wand do I have a level 51 chance to land a level 35 curse, or do I have a level 35 chance to land a level 35 curse?

Another way to put it, are level 30 offense scrolls/wands/talismans worthless at hero in PvP?

If you're level 51 and zap someone with a lvl 40 wand that has a level 20 spell of curse, you're casting with a level 20 spell.

Many of the really cool wands are things that are like...a lvl 20 wand with a lvl 30 spell, allowing you to cast "higher" than your level if you're level 20 at the time.

So...for the most part, yes, wands are often somewhat useless at high levels in that most characters have something "better" to do. Being able to knock a foe out and have ample time to re-use wands can often help, and there are a number of spells that the benefit can be well use the gamble.

Up to you to discover where they're useful and where they aren't!