The answer to the question of what does the i4 excel at? As owners of both. (my car is the AGT and my wife has the i4M50)
Apples and Oranges. The Air is a mid to large size sedan. the i4 is a small to mid size sedan.
My AGT is a better car, but costs 2x the price.
Pluses for the i4 are that it offers HUD as an option.
Acceleration of my i4M50(seat of the pants feel) feels faster than my AGT for the 1st 1/2 second, then of course my Air blasts out after that. Both cars offer far more power than 90% of EV drivers would feel they ever need(this excludes the 5-10% on this forum where you can never have enough power-myself included.)
The i4 feels a bit nimbler going around curves and feels faster off the line as I stated above.
The intermittent windshield wipers on the i4 actually work as intended.(Are you listening Lucid?)
The A/C vents can actually be directed so that air can be blown on your face.(no protruding lip of the dash as on the Air which interferes with direction).
The Air is more voluminous inside while the i4 can feel a bit cramped.
the i4 is a hatchback and the back seats can be folded down for even more room.
The i4's range is 270, which is fine for local and short trips but does not compare to the AGT's range which is almost 2x that.
Again, my AGT is a better car, but it should be for the higher price.
Both are great cars, but are different size cars and probably appeal to different audiences.
Between the 2 cars, the Air is my favorite, but both will appeal to EV drivers compared to the competition.
The Air is very fast, has great range, gorgeous exterior and interior, love the rear cameras on turn signals, etc. I like my Air best of the 2. My wife prefers the smaller size I4.
Hope that answers your question.