How good is it to collect calligraphy with few words?

It depends on the calligrapher himself and the size of the work. The number of words is only one aspect. For example, the founder Li Chuanbo's four-foot-three characters are close to 20,000, and the collection value is relatively high, while you want to collect the six-foot Chun Xue of the cursive writer Li Chenglian, only 3,000.