I have -0.75 power only in my left eye. Do I need to wear glasses, though I can see well and is this curable?

Nope, but you have very mild myopia. myopia is not a disease first of all it is a refractive error which can be corrected by the use of contact lenses for spectacles.

Secondly, no cure has been found so far to treat myopia.

Going for advanced techniques like Lasik or smile will only remove the need of your spectacles but will not cure myopia and second it there are where is disadvantages and advantages of going through surgeries I don’t recommend anyone to go for surgeries to correct refractive error.