I honestly prefer the IEC socket cord arrangement for a myraid of reasons.
#1. Easy as pie to find a replacement.
#2. Need a longer cord? Super easy to get.
#3. Eliminates the potential tripping hazard of an attached power cord.
#4. Allows one product to be manufactured and distributed for multiple markets without expensive and time consuming retooling / multiple product lines. Just design your product with a power supply that handles the various power inputs, and toss the right cord for the given region into the box and ship it off...
Your concern about forgetting the power cord is while valid, I would be embarassed to admit if I did forget something as important as a power cord, just like folks rarely if ever complain about forgetting the instrument cable, or say the speaker cable between head and cab...
You really ought to have spares in your gig bag anyway.
Those that read my posts know I somewhat recently went from a Crate BX-100 combo (now in the youth / teen ministry area at my church) to a Fender Rumble V3 500 combo. The Crate had an attached power cord, the Fender, uses an IEC socket / removable cord.
The biggest issue I had with the crate was portability. Weight being the biggest factor, but that stupid attached cord being the second biggest. The Rumble's detachable cord means I can remove that thing, toss it in my gig bag, and haul the amp without worrying about stepping on it, or rolling over it with hand truck wheels. No matter how I had that dumb attached cord wrapped up, it never failed, it always was in the way when moving that amp!