They seem to be present in most Asian cultures. The ones I've had were similar to fish balls, mildly sweet and quite different from other sausages in taste and texture. They weren't terrible but I didn't really care for them.
I used to eat them all the time -- and yeah they taste pretty bad. I'm the kinda guy that says flavor be damned, if I just need a quick source of protein.
They're usually sold in convenience stores quite cheaply as otsumami (booze food). Since I'm now engaged to health-food buff, the last time I reached for one, I was told to look at the ingredients list -- which was a mile long. The commonly sold variety just ain't that healthy.
As the Japanese economy took off a more western style diet was adopted, with a stronger focus on meat. As well sausages are typically lower quality/cheaper protein so an increase in wealth would correspond with a move away from sausages.