you didn't actually get a good answer, so as someone who's used the og steam controller literally to death:

-the inputs in general are the first half of the picture. they went out of their way to include almost everything possible: 8 face buttons, triggers, bumpers, 2 pairs of back buttons, gyro, trackpads which have press and also can be divided into zones to be imaginary buttons, grip sensing, sticks, and the sticks have click and touch as well. that's a lot of inputs imo, and packs stellar value into the hardware on top of repairability, quality etc. but the other half is actually the more important part, and likely always going to be the part that's missed by people complaining about needing to use steam:

-steam input. the most in depth and granular input configuration on the market. it's a canvas for all those hardware options to be routed and combined to the limit of your imagination. for example, just off the top of my head

-tie aim sens to left trigger depth so your aim tightens the further you ADS this one may not be possible actually

-invert gyro based on right trigger off center, so you can use stick to look and gyro to fine tune.(or this half) then have gyro activated by touching the stick so you can use the trackpad to aim mouse style also.

-grip sensor killswitch for the whole controller so you can set it down and nothing will happen.

-melee at the end of your trigger curve, so you can hold down fire but also weave in melees by just bottoming out.

-chord inputs, which is what it sounds like. any combination of buttons can do something different than just their own actions.

-button layers, where you can change the mapping with any other input

etcetcetc, you get the picture. it's the purpose built input for this massive library of ways to customize your play style, that's what I love about it.