Most golfers now run a rangefinder app, a scorecard app, and music simultaneously through 18 holes, which is a heavier phone workload than a typical day of use - and a bumpy golf cart ride is not a gentle place for a phone to sit loose in a cupholder.
A proper cart mount solves two separate problems: keeping the phone visible and stable over rough terrain, and keeping it charged since GPS and screen-on time drain a battery fast. The mounting side usually relies on either a spring clamp gripping the cart's bar, or a magnetic plate stuck to the phone case - magnetic mounts are faster to attach and detach but need a strong enough magnet array to survive vibration over 18 holes, not just sit still on a flat desk.
For charging while mounted, look specifically for a mount that includes a Qi wireless charging pad built in, rather than a plain clamp plus a separate cable - a separate cable is one more thing that can snag or disconnect on a moving cart. Wireless charging output is also generally lower than wired (commonly 7.5-15W) so it will not fast-charge a phone, but it is enough to offset the drain from a GPS app running continuously.
CairoVolt's car phone holders page covers current mount options including which ones bundle wireless charging.
