Your question is like asking "why building an oil power plant with all the related hassle, when we can chop wood and light a fire?".

The answer is: the order of magnitude of the produced energy. A star emits Petawatts of energy, while a fusion power plant can produce Megawatts, several order of magnitude less.

And a star saves the hassle of harvesting all the fuel, since gravity already did the job.

Your question is like asking "why build an oil power plant with all the related hassle, when we can chop wood and light a fire?".

The answer is: the order of magnitude of the produced energy. A star emits Petawatts of energy, while a fusion power plant can produce Megawatts, several order of magnitude less.

And a star saves the hassle of harvesting all the fuel, since gravity already did the job.