I don't know why money being digital would make it any worse for the poorer people. As long as they have inclusion in the system, the amount of money you have doesn't matter.
It will be not secure for any poor because it needs an internet connection for its operation which the poor doesn't have
That is beginning to change, most people now have a cell phone and an internet connection nowadays.
As it is quoted the inclusion of every party to this system will neither bring more nor it would make the situation worse(spread the poorness ,in a bigger time frame).
And to respond to your question(accounting the time from the start till the fully implementation of the system) : is this particular economy safer for poorer people? i am going to go with a yes, cuz people with less money tend to lose more slash what they earn or have, so if they are partially unable to reach those virtual numbers, they will be partially unable to spend or lose those numbers . Although with the pass of time everything should and will go to balance. The balance is where your average poor neighbor will find its way to spend and/or lose virtual money with means that will will surpass his/her knowledge. (fraud included)