This kind of meter is incredibly rare and is almost never used throughout an entire poem. As readers might imagine, writing a poem in which every line contains one unit of the meter could be very taxing. It may also, for some, not be worth reading. More commonly, readers will find poems in which some lines are written in monometer.
In some cases, a writer might use groups of three beats (as seen below) to create one single foot. But, the former is far more common. Examples of monometer being used throughout an entire poem are hard to come by. But, the use of this kind of meter within a few lines, or just a single line, in a poem is far more common.
Monometer