I've always wondered about the properties of a metal that make it "sound good"... Brass and Titanium don't seem to have general physical properties that are all that similar, which makes me wonder if one or the other isn't just a gimic.
You get this in speaker design. There are two schools of thought.
One says that a speaker cabinet should aim to be 100% rigid and inert. Manufacturers go to great lengths, including solid concrete cabinets, internal bracing, etc, to stop the speaker cabinet interfering with the cones of the drivers.
The other says that since its impossible to make a 100% rigid cabinet, that this is a dead end, and that what we should be doing, is looking for a way to harness the vibrations dispersing within a thin, flexible cabinet, and make them part of the sound rather than trying to get rid of them.
Titanium, going on its vaunted properties in bicycle design, is very compliant and this translates on a bicycle, to being able to better absorb and distribute vibration from road chatter. It may be that the same properties when applied to sustain blocks, allow it to absorb vibration in the same way. Obviously in theory this would be bad but it may have some unexpected effect alike to this.