Dan,
The overwhelming majority of my sequences are from scratch and are done in the keyboard. The best way is to start with the sequencer of the keyboard but the finalization of editing can be done on the computer.
If somebody wanted to edit an already-made sequence, I think they would go directly to the computer. But I do not do that because I write my own arrangements and sometimes, I even compose my own melodies.
For me, a sequencer is a tool and there is a place for both software and hardware tools. Dropping or limiting the sequencer of the keyboard can be, in my humble opinion, a big mistake an arranger keyboard can do.
I have a dream, that the people here in this forum will be able to create their own styles from scratch. That these styles will be of the highest quality and that they can do this with ease, confidence and enjoyment. Only then, we will see creativity increase and the prices of arranger keyboards decrease.