I thought the exact same thing when I opened the box: It takes a while to get used to, but there are another couple of tips that make it easier;
Hitting "R" brings up the 'relative' mode to enter a point; when the dialoge is open you can switch between relative and absolute modes as well as changing between X,Y and polar from here.
Hitting "Esc" is the same as clicking "Cancel" - it closes the box and reverts you to the pick tool. Next time you are required to dictate a point, the dialogue box will pop up. If you click "Close", it will not pop up again unless you hit "R"
Hitting "Enter" drops the point on the drawing - the dialogue remains open for the next point.
Hitting "Tab" or "," (comma) will jump you from the X to the Y (or L to angle in Polar mode)
NB: the program remembers the last point entered, so if you are entering the first point of something (like another line) with the "2D" dialogue in 'relative' mode, the first point is reletive to the last one entered. This can be 'overcome' by first hitting "W" (set last working point) and clicking on your start point, THEN clicking on the line tool - just remember that the first point would be 0,0.
While using the mouse to enter points, Hitting "O" puts on "ortho" mode, and "U" removes it - this can be done at any point while entering in points (without the "enter 2D point dialogue active), although you have to move the mouse to regester it.
All the snaps are linked to keys "M"-mid, "E"-end etc. it's easy to switch them on/off to get the right snap.
Double clicking on a line allows you to grab the end 'node points' and strech them ("Edit verticies" mode) - If you double click on a 'node point' when the "2D Point" dialogue was canceled, it will pop up again and ask where you want it moved to rather than entering into the verticies mode.
To exit this mode for this entity, you need to double click another line, click on the "edit selection" button, hit escape or the selection tool button.
The "Offset" tool (triangle) is REALY handy; type in a value in the box, hit 'enter', move the mouse close to a line to be duplicated - click. Type in another number, enter, click... I find this sometimes easier than drawing lines; once the offsets are in place, I make sure that "end point" snap is on and join the dots.
You will also find that the trim tools both trim and extend - as a rule of thumb, click on the line you want to keep.
Hope this helps.
Gadget