Well, yes, there's a difference between writing it and producing it.

If you're looking for a writing tool, arrangers are da bomb. As long as you don't want to do something they don't do well, like mix and match time signatures on the fly, or arpeggiate one part while you have normal chord recognition on another (arpeggiators don't care whet the chord IS, they just play the notes you play no matter what... this can lead to some interesting stuff an arranger can't do) you can do some pretty good final stuff.

But, at the end of the day, if you want to promote your writing at a pro level, they are going to want a pro level of polish and production. And that is VERY hard to achieve without a DAW to put the final polish on stuff. There's a reason you really never hear an arranger on a hit recording...

An arranger's job is to approximate a live band. But it's never going to fool anyone that it is one. Too much repetition. Take just the fills, for example. You'll never hear a real drummer repeat the same fill identically all the way through a song. You'll never hear a drummer play identically in the last verse than he did in the first. there's a build-up, a rise in intensity. Four Variations and four fills just don't cut it...

That's why, when you're done writing the song, it's time to take the MIDI data of the arranger's output to the DAW, and start editing some variation into things. Change each fill a little bit (or a lot!). Change the bassline a bit for the last chorus. Open the hihats a bit in the bridge, push the velocity harder on the acoustic guitars in the last solo... Add in some synced audio percussion to the drums (arranger tambourines are horrible!). Run the beat through a filter during the drop, sky's the limit.

Try doing all that with a hardware arranger sequencer and a tiny low res screen, pretty soon you are going to throw it out the window..! I've been a happy DAW user since the Atari days! I wouldn't use a built-in if you paid me!

Yes, I love my arranger, and am happy to use its built in sequencer to capture my initial pass. But the minute I'm done with the main take, it's off to the DAW for the grunt work..!

If your problem with using a DAW is distraction from the myriad options, try using a simpler DAW. Try the entry level versions of Cubase or Logic etc., fewer tracks, fewer editing options, fewer possibilities. You can always transfer the project to their big brothers for the final polish...
An arranger is just a tool. What matters is what you build with it..!