In my opinion, people who are not completely sure about bitcoin are unlikely to invest in it. Because people who really don't believe in bitcoin think that bitcoin is a bad asset. So with that, I think people who really don't believe in bitcoin are unlikely to invest in it. But if people who have a 15 percent level of confidence, maybe those people can invest in bitcoin. Because usually when someone already has a little confidence in bitcoin, that person has the opportunity to invest in bitcoin. So maybe the choice of words you used is not quite right, my friend.
There are some people who doubt bitcoin to perform well in future and is worth throwing some value into it, that will still be convinced to invest into bitcoin especially when they have someone around them who is encouraging them to invest in bitcoin and they will decide to give it a try because they are looking for a good asset that want to invest into for their future. I was able to talk to someone who feels that bitcoin is a ponzi scheme. He love drinking beer and saving his money in the bank.
I told him to give it a trial after some months, and he said he would. The money he saves in the bank from his monthly income, I told him to share it into four parts and use only one part to invest in bitcoin whenever he recieves his income which he did. After three months interval , he told me that he has started developing interest to increase the money that he is using to buy bitcoin because he was studying and learning about bitcoin after he first bought his first.
There are some people that will overlook something and show no interest in it but the moment that they start investing into bitcoin, they will want to know more about what they are putting their money into if they should continue or not. You cannot just have confidence in something that you don't have the knowledge about but experience through practice can build that confidence in you.