T-Rudder pedal kinematics follow some Tupolev aircraft pedals model, don't remember what...
This up-down operation was choose instead an conventional back-forth because for a virtual pilot siting in a conventional office chair this up/down operation is more comfortable, you keep heels on rest and move only foot tip, or you control rudder only with foot movement, instead foot/legs/hip of a conventional pedal.
https://www.youtube.com/watch?v=u4AEoNszaBoWhen sit in office chair with column/legs ~90 degrees this combined movement foot/legs/hip became tiresome with time.
Other advantage is that T-Rudder don't slide over floor, so don't need be attached, and the design is compact, easy to store when not in use.
I use T-Rudder for WW2 CFG (il-2's, DCSW WW2 planes) and for drive vehicles in ARMA3, with foots of course.
For "cockpit" certainly this design is not most convenient option, because if cockpit was made properly you will sit more low, what make more easy move foot back-forth like in real planes.
Other point to consider is the lack of brakes on pedal. For me this is not issue because I am used to British differential brakes operations in games: press the wheel brakes and move rudder for brake this or that wheel. T-Rudder emulate differential brakes via T-Link software using a joystick button for brake.
But if due cost the alternative is these "entry-level" pedals from Thrustmaster, Saitek, CH - most plastic parts and using potentiometer, spent a bit more and get T-Rudder, metal construction, bearings on pivots, contactless sensor.