As good as phone cameras are, they are still not a replacement for the DSLR. On the other hand, there are occasions in which you do not want to travel with a full photography arsenal.
Phone camera lenses allow you to extend the zooming capability of your mobile device. I especially like the macro lens that I have. In fact, a lot of the closeup images posted on this site are taken using my smartphone with macro lens.
In the image below, I have my mobile lenses next to a regular DSLR (lens 18-55mm) to give you a visual comparison. The smaller lenses are about the size of a nickel (2cm) and the telephoto lenses are about the size of a small lotion bottle that you get in a hotel (6 cm). The photo caption provides some additional details.
I would recommend investing in a few mobile lenses or get a kit. Its a fun alternative to regular photography when you want to be a little less serious.