It is not just that, but the need to remember to charge it as well. I think that the people who are wanting a keyboard confuse what a tablet is best suited to.

My mother's 71. She has an iPad.
I bought her a bluetooth keyboard that doubles as a clamshell cover for it, so it'd always be to hand.
It's been used twice, before being left in a drawer.
She much prefers the touchscreen interface.

After years of using computers, it is something that annoys me about iOS and to a lesser extent Android, you can't access the settings of an app, when you are in the app. You have to leave the app and start the settings app and them search for the app you just left in the list, on order to find its settings. That is illogical in many ways.

I appreciate that all settings are in one place, but in Windows or OS X, I can quickly change a setting on the fly in an app, in iOS, I have to go through a couple of loops to make those changes and see how it changes the app.

From the stats that 'Merican web sites keep putting out, keyboards are either the second most sold accessory after cases for iPads.

To be honest, I don't use the keyboard on my tablet that much, but there again, if I am going to be writing long replies, I'll wait until I can use a device with a full sized keyboard. What I really like with my tablet is that I can just write on the screen with my Wacom stylus and it will convert it into text. It is also very accurate. Great for taking notes in meetings.

Like you I prefer to use a proper keyboard on a proper computer if I have to type. That does not mean I do not read those same documents on a tablet. I prefer to write and complete the document on my iMac and then will keep a copy on my iPad if I want to review it.