A front suspension fork absorbs impacts from bumps and uneven ground before they reach the rider's hands and arms — genuinely useful on rough, unpaved, or trail terrain where the ground itself is the source of most discomfort.
On smooth paved roads, that same suspension does very little useful work, since there's little terrain impact to absorb. What it does add is weight (a real factor when pedalling uphill or accelerating), and a moving part that needs occasional servicing to keep performing well.
A rigid fork — no suspension — is lighter, needs no servicing of its own, and transfers pedalling effort more directly. For city and paved commuting, a rigid fork is usually the more practical choice; for regular unpaved or trail riding, suspension earns its extra weight and maintenance.