Back cutters make the milling process a little different.
If you go with several passes to the final cut, the fence is progressively moved into the bearing (rub collar) and the backcutter bit is set to height from the get go.
With out the backcutter, you can progressively raise the bit to final cut and the fence is set to position from the get go.
No problem with either way and most times the back cutter allows for a fixed thickness of edge to insert into rail and stile. The "plain" cutter allows for custom edge thickness if needed.
I usually end up backcutting regardless, unless I'm using thinner panel stock.