The idea behind the linear turntable was that it would reproduce more faithfully the original recording, as the master mould for the vinil pressing was made with a linearly moving "grooving" head. Theoretically, in a fixed axis radial arm the difference in angle of the needle vibration relatively to the original orientation of the recorded grooves is a distortion factor (second picture below), that can be avoided by the linearly moving arm (first picture)
(In the picture "needle movement" refers to the vibration of the needle cause by the grooves, not the movement of the pickup head along the record.)
As with many other audiophile features, it's arguable if linearly moving arms allowed for any audible improvement, and modern manufacturers have not adhered to this technology (at least, that I know, not yet).
Regarding disk wearing, I don't see how it can make any difference, as the needle is round, so presenting the same shape regardless of the angle at which it is positioned inside the grooves, and so is going to offer the same resistance and cause the same wear to the grooves.