Of course ordinary citizens can use bitcoins. But, the catch is that, they will not be able to use it properly unless they have atleast some knowledge about cryptography and security. A lot of terms used in the community will leave them confused. But, the thing is that anyone can learn something if it is an interest or a necessity. Just look at computers 
Yes it is , but we should consider the fact that before someone can be able to use bitcoin thy must have gadget , Internet connection and specially enough knowledge for them to access it cause we all know that bitcoin is a digital system and its kinda techy we should be guided by someone who has a enough knowledge in this system.
It can be used by ordinary people but they can't make profit from it. They can only "USE" it that's all. No benefit, profit, anything good.
One must be rich to take the advantage of bitcoin.
Really are you sure of this? That ordinary people cannot make a profit to it and that they can only use it, are you sure of that? It seems ironic that you will only be able to use bitcoin of you are going to ise it. Basically bitcoin has mo reason why there is a need to know the gender of the user and even the status of life.
Yes right no matter who is using bitcoin and what his life style is, can make profit from bitcoin. Ordinary people can make profit from bitcoin as it is easy to use and you need only a computer and primary computer skills to operate. And bitcoin is a good source of earning for an ordinary person.