My understanding is that, as you said, the purpose of the mask is to stop droplets from coughs and sneezes from getting to other people and surfaces. However if

My understanding is that, as you said, the purpose of the mask is to stop droplets from coughs and sneezes from getting to other people and surfaces. However if others cough on you when you are wearing a mask, the rest of your face is still exposed so you are not fully protected, and you can still be infected by touching contaminated surfaces and then touching your face. Surgical masks are also not sealed off, so you can breath in aerosol from other people's coughs even with the mask. Certainly masks will help to some degree, as they will filter out some particles and protect you if someone directly coughs into the mask, but I don't think they are effective compared to things like hand washing. I am not a doctor, not medical advice.