Slightly off topic rant::::
Nobody should be selling/using pure tungsten electrodes.. It's the 21st century fellas.
At least don't spend any more coin on them... If you are so Dutch that you feel you must use up what you have? Ok,.
The reason Miller recommends that pure tungsten not be used with their inverter based power supplies lies in the fact that pure tungsten does not have the alloying elements that improve the "work function" of GTAW electrodes. The "emitters" in Thorium, lanthanum, cerium and zirconium allow for better arc starts. The capacitor discharge type of arc starting that are built into inverters is a little different than the High Frequency arc starters in transformer based power supplies. This difference has an effect that makes arc starting more difficult with pure tungsten electrodes... Will it hurt anything if you use pure tungstens with an inverter power supply? No.
Spend the extra 5 bucks a box and buy cerium or lanthanum. Both of these work well with both AC and DC. Or if you are a dedicated AC aluminum person, Zirconium is also an excellent choice.