Titanium knives were developed for non-magnetic and non-spark applications. This is Industrial mega knife/scraper/grinder applications. They were superseded with Stellite and Talonite cobalt alloys. Knives can be had in Stellite and Talonite as well, but they're very expensive.
Titanium is softer than steel. It's stronger than steel by WEIGHT. So you get a lighter blade that is softer. Titanium doesn't hold an edge well. It is set with carbides for the cutting edge. Carbides also do most of the cutting in steel, but they form naturally in high-carbon steels.
They can all be home sharpened as usual.
Outside of some specialtly niches as noted above and for saltwater diving, better knives are available in steel than you can get in titanium. The Stellite and Talonite blades are VERY good though.
