An indirect answer to your question: when I had a Birdy, it had a 9-speed Capreo setup. I think the gear-range was roughly 30"-90". I went loaded touring on it (tent, food, everything!) in California (think hills!). Although I occasionally wished for lower gears, overall I thought it was a great compromise setup for lightness/simplicity.

So - for your intended usage, it sounds like a good idea. On the other hand, there's no real downside to riding a 3x8 setup to work, and a not inconsiderable investment in changing it.. Depends how strongly you feel about it