Where I live and worked (in Spain) weep holes are common in visible retaining walls but no towards under the indwelt area. In fact I have never seen this arrangement here put unto practice. I am assuming you are talking of no habitable cellar. If habitable, then this kind of thing maybe would be used to channel the water to some sump pump. The only case in which something similar I have seen was one case where the gravels under a 1st underground level parking lot besides a river was left connected to a sump pump, single instance in over 400000 m2 built.
Respect what effects it can cause, varies with what kind of supporting ground you have. If you stand in sound gravel plus sands unlikely to be washed by changes in watertables, the effect will be from moderate to nil.
Contrarily if the soil is clayey and of the kind that heaves with changes in water contents, you may be adding one source of water that has some potential to unleash the effects. These crounds are rare, and normally weep holes could be ineffective due to the clayey nature. In any case I think for these cases a good separate but sealed pavement would be a better solution than attempting some equalization of the water contents outside and inside, for I think is better to the interest of the building that the water contents of the soil under your building be constant, this leading to stability and absence of movement in your building, this at least versus the I assume intended of the soil under your building follow any stational variations in water in the surrounding soil. The weep holes may of course diminish very much the pressures against the wall, since the water content is inmediately drained; and surely this has been the main iontelligence of the building, and the practice originate in the sleeper foundations being only proper for bearing vertically the walls, and in no way or very scarcely the earth push of the retained earth.
