Katakana looks cool for Japanese
Katakana characters are basically to be used for imported words (nouns), take Banana, Gorilla, Computer, Smart Phone, for example. This notion has changed recently that people today, especially people engaged in advertising business, use Katakana as alternatives to Kanji or Hiragana, aiming to enhance the image. It seems effective use of Katakata is crucial to create catchy names, for products or company's.
Hiragana is Kawaii.
Although Katakana is getting popular, it doesn't mean Hiragana characters have lost their charm from the cute or Kawaii looking. and young people (especially girls) love to use them very much.
In fact, I use Hiragana to write “Thank you” to friends as it looks warm and friendly. Thank you in Hiragana is; ありがとう For business letters, I use the mixture of Kanji and Hiragana as it looks more formal. Thank you in Hiragana is; 有難うございます Thank you in Katakana アリガトウ is rarely used as it looks rather cool.