These are great little notebooks, that are tough and last well. There are many advantages to a paper notebook or journal, including how long lasting it is. Making notes on your phone is fine until you need to change the operating system and then your notetaking program turns out to be in some custom format that can't be exported to another app... Argh.
Paper, is simple robust and reliable, never runs out of battery and encourages a different attitude to writing. All your mistakes are preserved (but that can be a good thing). It charts your progress through an idea and makes you take the time to express your thoughts throughly, as there is no auto correct to pick you up.
The notebooks themselves have a stylish black cover, bookmark ribbon, handy pocket and are held together by a strong elastic band. They look timeless and understated so you needn't feel odd about writing in them in public. This smaller one is a handy size for my jeans pockets so I can take it with me an record my ideas on the go.
Remember computer files are usually obsolete and unreadable after 10 years but we still have the hand written letters of famous people from Abraham Lincoln to Beatrix Potter. Paper is the future...