Thank you all,
tgauchat, I’m not currently in this situation, as I said in my first post, this was just a test to see what would happen if I lost my phone.
I understand that we should secure our phones, and also I am aware of the Find My Phone feature, but as scottinpollock pointed out, none of those should be an excuse, this is an app that can open your house if you have a smart lock. This is like if I lost the keys to my house and the locksmith told me "I’m sorry, I can’t change your locks and so you can’t prevent the lost keys to be able to open your house. I consider this as a mayor security problem and think that it should be fixed ASAP.