Using a smartphone app as a gym interval timer is a viable option and offers several advantages: Convenience: Most people carry their smartphones everywhere, making it easy to access the interval timer app anytime, anywhere. Cost-Effective: Many interval timer apps are free or available at a low cost compared to dedicated devices. Feature-Rich: Interval timer apps often come with a wide range of customizable features and pre-programmed workouts. However, a dedicated interval timer device might be preferred by some for the following reasons: Visibility: Dedicated fitness timers have large displays that make it easy to see the time remaining in the blink of an eye. Timers also work better for groups. Features: Loud buzzers, large digits and many presets are often not found on timer apps. Durability: Designed specifically for fitness use, dedicated devices are often more durable and resistant to sweat and impact. Reduced Distractions: Using a smartphone app might lead to distractions from notifications or incoming calls, while a dedicated device is solely focused on timing workouts.