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I know this is old, but I had the same problem. However I came up with a better solution. You may make a grid in the guide layer consisting of lines with equal distance. (Setting the em value to somewhat between 10 & 60 and using Ctrl+C/V and the cursor keys might help with this, Afterwards you can reset the em value to 1024 or whatever you like.)
Still the curve points won't snap to the intersection points of the grid, only to the lines, since they only snap to one line at a time, but not two. To solve this, you have to add a point exactly at each position where two lines intersect. (Again, a low em value, Ctrl+C/V and the cursor keys are extremely helpful)
With this approach you end up with a grid that works similar to the one you are used to in programs like GIMP. However it turns out to be really slow, even on high performance computers. So a real "grid functionality" would still be really beneficial. Is there one? And if not is there a reason why there isn't one? Because this is some really basic stuff that you would expect in any graphics program.