If you're looking for a fun plane read, or a way to make friends at a bar, this is the perfect book for you. It has a ton of phrases that will keep you interested way longer than your typical textbook "Hello, how are you."
On the other hand, if you know enough Japanese to get to a conversation where you would seriously use one of these phrases in context, proceed with caution! Often the Japanese is written in a certain politeness level or with a gendered manner of speech that may be inappropriate for that situation. Also, there is very little context given for the Japanese word, and sometimes the meaning is slightly different from the English equivalent (think about the difference between "Oh my God!" and "Oh my goodness!" and "Great Scott!" Now imagine not knowing the difference between these and picking one to use in conversation!) Sometimes the Japanese word--or even the English word!--are unrecognizable to native speakers!
It would make a good gag gift or borrow it from a friend, but look elsewhere for a genuine phrasebook.