I discovered the value of taking along a laptop in 2000, when I took along my Compaq LTE because digital memory was so expensive then ($100 for 16MB). I found I could review, edit, and organize my photos, bring along vital info (like addresses and rail schedules), keep an expense report and forecast how much I needed to complete the trip, and record my journal. After that I invested in a lightweight (2.4#), used handheld. More recently I bought a "heavier" (2.9#) notebook w/Win 2K).
It's not a toy (I don't watch movies or play games); it's a useful tool.
If you recognize it's usefulness, take one along, but if you need a wheeled cart, you are doing something wrong. There are plenty of inexpensive, lightweight (usually used) notebooks on the market. At their low cost, theft, except for the value of the information, which you wouldn't have anyway if you didn't bring a notebook, is not a worry.