Mike:

It has to do with practicality more than anything else.

First of all a 2wt is best used on flies 16 and smaller when there is little or no wind on smaller fish. I have a 2wt and it times I love it but if conditions are not right it can be a pain in the butt to cast. I am not positive but using a 2wt as an example I would imagine that when you get to 1wt rods and 0 or 00 you probably are talking about flies smaller than 20 on days when it is deadly still. I guess if you can be sure that?s what you will encounter it?s OK but in my experience the day you take the 2wt-00wt out for a spin there will be a Hex hatch.

The other issue is available lines in those sizes. There just isn?t a decent selection of lines out there in the smallest sizes and a line can make the all difference in how a rod performs, I personally would never buy a rod that required a special line from a single manufacturer. I will guarantee you eventually it will be discontinued and you will be in possession of a 00 weight tomato stick.

And finally many fly fisherman just don?t think that it?s fair to fish in places where bigger fish lurk with ultra-light tackle; it MAY necessitate the need to over-play a fish and possibly kill it.

I personally have no use for anything smaller than a three weight although I already own a two weight rod. And don?t be fooled into thinking you need to go small to fish small; I fish regularly down to size 28-32 flies and use 3-6wt outfits to do it. The 1-00wt outfits are cute toys but better suited to be conversation pieces than fishing rods.