For genuinely small jobs, often yes. Tightening a loose screw, gripping a stubborn fitting, stripping a wire, trimming a zip tie: a multi-tool handles all of them adequately. What it cannot do is sustained work, because short handles mean limited leverage and limited comfort.
One-off adjustments and repairs away from home. The comparison that matters is not multi-tool versus toolbox, it is multi-tool versus nothing, and by that measure it wins constantly.
Assembly of flat-pack furniture, bike adjustments on a ride, and tightening things that have rattled loose are all firmly in scope.
Anything repeated. Twenty screws with a multi-tool driver is an unpleasant twenty minutes that a screwdriver does in three. Sustained plier work is uncomfortable because the handles are short and often hollow.
Torque is the honest limit. Short handles cannot generate the force a full-size tool can. See can a multi-plier replace pliers.
Bit drivers with real bits beat integrated screwdriver blades by a wide margin, because you can use the correct tip rather than an approximation. Look for that if repairs are your main use.