Are Skew & Fishtail Chisels Needed?

The half blind dovetail is a perfect example of an action where skew or fishtail chisels can be useful.  Maybe.  In cutting this joint I do illustrate where and how these different chisels can be helpful but I also show how to accomplish the same this with a regular old bench chisel.  Moreover with a half blind dovetail, half of the joint is hidden right so undercutting is possible to avoid having to clean out the inside corners completely.

In the end, having a fishtail chisel or a skew chisel around isn't terrible.  Its better to have the time saving tool than not when the situation arises.  But like all specialized tools, I would NEVER let its absence hold you back from something and I would definitely not put it on your buying list for a while.  At least not until you have all the other common use tools in hand.