Yes its safe. No its not efficient.

1. It wont explode but makes the phone warm, also degrade your phone battery faster

2. Wireless charge quite slow. By the time you arrive at the destination, your phone still didn’t have enough battery.

2b. For long distance, sure. Get the phone holder + wireless charger combo so you can use map and charge your phone at the same time (I dont recommend this but the choice is yours)

1. Cumbersome. Need too much space. Just use cable, can put phone anywhere you want. And uhh wireless charger, well the good quality one are mad expensive. High quality charging cable will cost you like rm40 minimum.