Most Japanese people have no problem reading 'Romaji'. They'll find it just as easy to read the word 'Hotel' as they will 'ホテル', so it leaves plenty of scope for using both in graphic contexts. It can be useful for headlines, titles and headers and - simply put - it looks more interesting to mix them in that way. 'Romaji' text is simply everywhere in Japanese life.
The majority of Japanese people alive today will have learned English as their second language and they will encounter plenty of it in their daily lives. Romanising Japanese words is also quite common. Nobody would ever think to question the huge signs on the outside of Japanese department stores and supermarkets like 'Isetan', 'Takashimaya' and 'Ito-Yokado' being written in 'Romaji', even though their original names were written in Japanese Kanji characters.
Same thing has always happened with cars. Nobody would think it unnatural that the 'Skyline', 'Fairlady, 'Crown' and 'Civic' emblems on their respective cars were written in 'English' when they can be written in Japanese Katakana phonetic characters as 'スカイライン', 'フェアレディ', 'クラウン' and 'シビック'.
Hard to explain, and possibly all the more so because the Japanese seem to hardly even consider it odd in any way. Its just natural.