1. The tape format is as valid as any other music listening platform.
2. It’s compact and easy to use.
3. A portable tape player doesn’t need recharging, as it takes standard batteries. Meaning, if it goes flat while you’re out, you can always replace them without the need of trying to find a charger.
4. It lets yo concentrate on your music more. In the modern age, people are very fickle due to the convenience of shuffling and playlisting - with listening to a tape (like a CD or LP), you can concentrate on one release, and given the portability and convenience of such a small size, it is more accessible than a CD or LP.
5. Like listening to vinyl, tapes have their own equivalent to the ‘crackles and pops’. There is a unique quality to it, which is both charming and eclectic. 
6. It has the convenience of being able to manually stop the tape at any point and holding a part so you can come back to it later. Like them VHS things from the old days. Also, due to vinyl being a very placed track process, the ease of tapes when skipping through parts of songs make it even more user friendly.
7. The size of cassettes (and their portable players) are very small and light weight and easily stashed in either pocket or bag. 
8. There is a nice aesthetic to the size and casing of a cassette, from the rectangle nature of the front cover (and its foldouts) to the colour of the tape and the design on the label, to the cute case, spine and lip.
9. Again; because of how compact they are, they are easily shared.
10.  And finally because you can create mixtapes and mixtapes are damn cool. There is nothing in the same league of fun as creating or receiving a personally made cassette (maybe with a cool handmade cover and case). Think of making your own radio show, or audiobook, or personalising a mix on a music software and recording it prog rock style as a beautiful listening experience. 

In conclusion, to all the people who want to bandy the idea that tapes are either dead or useless now, we like to believe contrary to that. And these reasons are good enough.