the thermostat valve is there to block coolant flow to the radiator until it reaches its opening temperature - usually 80-85 degrees celcius - after that it opens up and coolant flows to the radiator and tripping the cooling fan circuit causing the fan to run.
The t-stat also ensures that coolant gets into every little area of the engine as it causes the coolant to slightly pressurize too, It also ensures that your engine does not overcool on highway runs
removing the stat would be forcing the engine to take forever to warm up - exact same useless thing as running without a Tstat