ABS and many other materials require a heated print bed. This doesn't have that.

From what I understand, only PLA, Nylon and one or two kinds of PET are realistically printable without a print bed. Nylon has quite a stink while printing, and PET varieties are generally more expensive than most people want to mess with. Therefore to keep costs down, a lot of printer makers are leaving out the heated bed and putting "PLA Only" on the printer.