Not necessarily. The cost of backtracking on a bad branch prediction on a device like a phone may be so great that implementing an ANN could be worth the effort to implement.
I'm not as familiar with mobile phone architecture as with that of PCs, but the number and types of operations influenced by the device's various sensors (light sensor, GPS, accelerometer, gyroscope) could conceivably be more than normal, naïve branch prediction can handle effectively.
Why would speculation invalidation be more expensive on a phone? If anything, many phone CPUs tend to have shorter pipelines and less expensive branch prediction misses.
Also I do not see how the number or quality of sensors could in any way affect the prediction rate.
I'm not as familiar with mobile phone architecture as with that of PCs, but the number and types of operations influenced by the device's various sensors (light sensor, GPS, accelerometer, gyroscope) could conceivably be more than normal, naïve branch prediction can handle effectively.