I honestly don't understand the advantage of using the paddles. I used them for a few weeks (usually going through all 4 stages) and noted the charging taking place on the display, but when I used the brakes instead I noticed a significant increase in the charging, sometimes double according to the display. So the only reason I can see for using the paddles is to reduce brake pad wear, or when going down a long hill to prevent the brakes from overheating. Can anyone shed some more light on this topic?
The paddles use regen only, so they are the most efficient way to slow down, whereas the brake pedal uses a combination of friction brake and regen. However as far as we know except for hard braking the brake pedal still uses mostly regen and only a little bit of friction braking, which we think is to add smoothness. The Clarity is often complemented on its smooth braking using the pedal compared to some other hybrids and EV's, so that is likely why they blend in a little bit of friction braking.
There are anecdotal reports that using the paddles as much as possible improves EV range, but there are no hard numbers that I know of quantifying this.
Of course if you need to slow down faster than the maximum that the paddles will provide then you step on the brakes. Contrary to some people's misconception the brake pedal still uses regen, in fact as you have observed the brake pedal will use a higher level of regen than the maximum paddle regen. But it does come with a little bit of brake pad wear, and also a little bit of lost opportunity for regen.
Right now we don't know how much brake pad wear but probably not much, this will all become more clear after more people get to high mileage like 50,000 plus and we start to find out how much the brake pads are wearing. On my Prius I drove over 150,000 miles on the original pads and they still had plenty to spare, that's because the Prius only used friction brakes for hard braking, and also for the last few mph before stopping as regen doesn't work well at extremely low speeds. Whether Clarity with its blended braking will have similar low brake pad wear we don't know but it should be pretty minimal even for those who mostly use the brake pedal.
Also some people like to drive in Sport mode where they can activate full regen with the paddle, which then stays at maximum allowing them to do sort of a Clarity version of one-pedal driving like people do with EV's. In the other two modes full regen only lasts briefly then shuts off until you press the paddle again.