If your foundation walls leak the best place to address that issue is on the exterior. Interior-applied systems will not hold up against hydrostatic pressure. And a good exterior foundation waterproofing system will include a good foundation drain system and a drainage course (gravel or composite drainage board) over the vertical membrane.
If the foundation walls are CMU, an interior coating will also serve to keep the water in the CMU (which is vey absorptive, and will likely have open cores), so the water will usually flow down to the slab level and then seep out of the CMU onto the slab surface. That results in flooring system damage, and possible damage to the bottom of the wall finishes.
If the foundation wall is cast-in-place concrete, it should only leak at cracks, control joints and/ or penetrations. These can usually be dealt with with urethane grout injection from the interior. And supplement this by making sure all downspouts are routed to discharge away from the house and make sure the soil surface slopes away from the foundation as well.
If the foundation walls are CMU, an interior coating will also serve to keep the water in the CMU (which is vey absorptive, and will likely have open cores), so the water will usually flow down to the slab level and then seep out of the CMU onto the slab surface. That results in flooring system damage, and possible damage to the bottom of the wall finishes.
If the foundation wall is cast-in-place concrete, it should only leak at cracks, control joints and/ or penetrations. These can usually be dealt with with urethane grout injection from the interior. And supplement this by making sure all downspouts are routed to discharge away from the house and make sure the soil surface slopes away from the foundation as well.