Connect Digital monitor to Arduino?
It all depends on how used to you are with using pi or arduino. What you want can be done in both ways.
The displaying of count is common for both. It can be done using a 16X1 LCD display, 5 different 7 segment LED connected via decoders or a graphic display module. Interfacing all these with Arduino will be relatively simpler than Pi.

For the fetching of data and sending it to your device for displaying it. You can use ESP8266 Wi-Fi module with arduino and pull the data. Which is not as simple as it sounds but it is not impossible too.

For pi, (like @max246 said) you can run a python script and use another api to get the data.