Yes, absolutely! All downspout extensions will provide some additional protection for your home’s foundation, although some options work better than others. A splash block, for example, is much less effective than an underground drainage system, but both will help move water away from your home, thereby helping to avoid issues like:
Foundation cracks
Leaks
Increased humidity in your home
Pest infestations caused by high moisture content in your home
Mold formation due to moisture