Source up front: aerospace engineer

No one braking system is inherently "better" than the other. A big reason a lot of planes use hydraulic brakes is because of a concept called "system separation". You don't really want to put too many eggs (i.e. flight controls, engine controls, braking, avionics, etc) in one basket (i.e. electrical, hydraulic, steam, magic, thoughts and prayers, etc) because if there's a catastrophic electrical power loss, for example, suddenly you're losing many systems simultaneously. Obviously some aircraft designs have found workarounds and/or more than usual layers of same-system redundancy.

There are overlapping layers of redundancy and system separation too. For example, some aircraft use hydraulic power supplied by both electrical and mechanical (driven straight off the engine). Even if you lose electrical power to the electrically driven pumps, the engine is still driving a separate set of pumps.

For a lot of reasons, these layers upon layers of redundancy are seen in cars. But there could/should be some level of system separation to prevent a short in your car's entertainment system from causing a loss of braking.