Til that Togashi considers Biscuit an 'Ultimate Transmuter' which in terms of proficiency with Nen is the highest possible proficiency above great, excellent and genius in his books.
To put that into perspective, series antagonists and powerhouses Neferpitou and Hisoka, only have Genius level proficieny with their nen category. Meanwhile Bisky is on the same level as Meruem and Netero which are two of the most powerful Nen Users we've seen in the series. Not that 'proficiency with nen' directly corresponds to power but its pretty funny coming from a lady who whose main ability seems to be summoning a masseuse who relieves fatigue.
I think this may says a lot about how in Togashi's works a lot of thought has been given into how strength and skill are relative. It's also hard not to see the real world parallels to this. Togashi himself has been struggling with health issues such as fatigue for a long time now forcing him to go on hiatus multiple times whilst working on HxH. I'm sure he would absolutely love to have Bisky and her abilities in his life and definitely wouldn't value Hisoka's bungee gum as much.
This new HxH Itajaga set comes out later this month, with 26 brand new character illustrations on metallic cards! Itajaga are like a cracker/snack essentially, and the cards come randomly packaged with each one. I bought 5 boxes of the last set and managed to get two full sets plus lots of extras. I'll probably do the same with this set!