The bank angle on a train track is calculated for a given maximum speed, as trains do not have the option of choosing their line as would a car on a banked track. High-speed lines have large radius turns, to minimize the slowdown.

If the train goes slower, people will 'fall in', as noted by luxury. Tilt trains do not address that problem.

To go faster in turns, the only option short of laying new track are tilt trains. While lateral loads on the passengers may be limited, they will certainly notice the extra tilt, especially since there is a plane of reference just outside the windows. On less smooth implementations such as Fiat's Pendolino, motion sickness is common.

Tilt trains are just a trick to gain a little speed through turns. As tilt trains subject the tracks to additional lateral loads, they are all are lightweight, reduced cross-section aluminum constructions, not optimal for high-volume lines. The one exception is Amtrak's Acela, way overweight due to obsolete US crash regulations; predictably, this train suffers from excessive wheel track/wear and cracking in suspension components.

That said, many next-generation high-speed trains (TGV and Shinkansen included) are slated to be tilt trains, due to saturation of the original tracks (the TGV Sud-Est and the Tokaido Shinkansen being the busiest rail lines in the world).

On a different note, my favorite train so far is JR Kyushu's Kamome, operating on the narrow-gauge Hakata-Nakasaki line. Next would be DB's ICE3.