Katakana Samples

#1. Hisamitsu Mask
          -スクワラン ,  コエンザイム, ダブルでカバー
          -foreign words/technical terms/emphasis(?)

Here katakana is not only used for foreign scientific terms like: "squalene" スクワランand "co-enzyme" コエンザイム but it is also used for words like "double cover" ダブルでカバー . Double cover is written here in Katakana but it is not a scientific term. Why is this?



#2. Shiseido Anessa Sunscreen
                     - プロテクター ,  シミプロテクト , ダメージプロテクト
                     -Emphasis/foreign words

 Here they use Katakana to spell out the word as it sounds in English: "protector" プロテクター. Why did they decide to do this? Also when listing the types of protection, Katakana is used instead of the normally used Hiragana words. Why?



#3. Shiseido Aqualabel: Deep Clear Oil Cleansing
                     - プラ ,
                     -Emphasis

Notice that the recycle symbol uses Katakana for "pure" プラ instead of the Japanese word さいじゅんかん　or the foreign word Katakana リサイクル for recycle. What is the purpose of doing so?