UHA - pleasant banana WTF

Hello, Foodies! Today I have for you something called ごきげんばなな (gokigen banana) made by UHA. Gokigen means something like "pleasant¹" (I think, but it's hard to say, because it's written in hiragana without any kanji) so here we have pleasant bananas, uh? WTF, Land of the Rising Sun?

 Packaging 

Oh.My.GOD. It's adorable. ╰(▔∀▔)╯ Maybe the main foil (the biggest one) isn't very special, but look at these small, single ones. They're so cute!

And what's more they try to talk with us.＼(≧▽≦)／
Red one says "どこまで細くさけるか挑戦 しょう" (doko made hosoku sakeru ka chōsenshō) which probably invites us to try to detach the thinnest part of these banana funny gummies.

Blue one says "まちがいはど〜こだ？" (machigai ha do~ko da?) which encourages us to find differences between two pictures.

And it's not over yet! White ones just have names of the product and little note pattern.

But look at yellow ones!
They say "今日のごきげんみくじ (kyō no gokigen mikuji) - today's gokigen fortune
中吉 (chukichi) - "middle blessing" (kind of omikuji - traditional fortunes written on strips of paper at Shinto shrines in Japan, here just blessing on the packaging)
"ごきげん爆発まであともうすこし" (gokigen bakuhatsu made ato mō sukoshi) - I'm not sure what it means, but I think it's something connected with explosion of gokigen² ^^' Cinek, I need your help here! 

So... for a lot of fun I gave them...

4.5 / 5

 Novelty/Appeal 

Finally we leave Japanese adnotations alone and we focus on the sweets. Let me cut to the chase: fruity gummies aren't really surprising for me. But funny foils make those treats cute and surprising.

4 / 5

 Taste 

Well... they were good. Maybe the taste wasn't as awesome as the idea of fortune-telling wrappings, but still relatively good. They have soft flavour of bananas mixed with yoghurt. Softly sweet and definitely addicting.

9 / 10

 Final score 

4 / 5 

- - -

But I still don't understand one thing... why is ばなな (banana) written in hiragana³? 

Usually we use katakana for English words in Japanese, but here this rule is broken. 

I don't get it... ┐(￣～￣)┌

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¹ I think it's just "happy", but I like your dirty talk. I quess "explosions" ARE pleasant./Cinek 
² "Just few more minutes untill the explosion of happiness."  I quess that IS a good fortune and pretty Nostradamus-like accurate at that.  /Cinek³  I asked people who know japanese people to ask them about that. Got no explanation, asked japanese people myself. Got no explanation either. All I got is that this is a company gimmick. /Cinek