One additional point with noting is that there is a limit to how much energy you can capture during regen - you fairly quickly reach a point where you're putting too much power back into the battery, which risks overheating the batteries and causing damage. It's no different to having a maximum charge rate when you plug the car into a charger. Heavy regen can also cause stability issues, especially on rear wheel drive vehicles - you can't only brake the rear axle without destabilising the car, so the front also has to be braked using the normal brakes.

On most cars, that limit is in the range of a braking rate of around 0.3G to 0.4G. For that reason, brake blending (using both regen and normal brakes) has to be done. Although 0.4G braking is well within most normal braking events, cars will actually be able to brake at a minimum of 0.9G, and some will be able to go up over 1.2G.

Recent battery technology has improved to the point where it's not so much of a concern. As recently as 5 years ago, the max brake rate you could capture regen from was around 0.2G.