Frequently heard, but I suspect the people suggesting it have never done any data input work involving lots of numbers.<p>I could argue that you don't need a mouse. If you're moving from keyboard to mouse so frequently, why not learn how to do things without the mouse?<p>I had a job in logistics where I often had to train non-IT professionals to handle data input involving mostly numbers. Most of them had never used the numpad, half didn't know how to move around using tab/shift-tab and didn't know keyboard shortcuts. They would rely heavily on the mouse. When I trained them to use all these, and forced them to use by removing the mouse, their productivity would increase by several hundred percent in some time-consuming data input tasks. The software was Microsoft Dynamics and Excel. Most of them were frustrated at first, but became proficient within a week or so, and would continue to use the keyboard even after reintroducing the mouse.
Line-of-business apps and heavy data-entry tasks are the exception. Every enterprise is full of them. Navigating across fields/buttons using the keyboard without using the mouse is a huge productivity factor in those scenarios.<p>A good metric to use in these scenarios is effective keystrokes per hour. Several years ago we did a study while building a remittance processing system for a financial institution and found that just doing 'amount entry' (fully numeric input only) increased the effective keystrokes per hour compared to mixed mode entry. That means higher items processed per day (which translates to $$ transacted).<p>There is a marked productivity difference between doing numeric only entry using the numpad versus the numeric key row at the top of a keyboard. The numpad is orders of magnitude faster.
Unfortunately, I do need a lot of these redundant keys. I had the entire Numpad set up as hotkeys in AutoKey.<p>So yes, I don't need Numpad, and I don't need NumLock, scroll lock, insert, function keys, function key, Super key, dedicated backslash key where the return key used to be, maybe I don't need caps lock, right-hand shift key, I definitely never touch any of the mod keys to the right of the space bar. I don't know much about AltGr whatever that means. I don't need right click or a dedicated key for it. I should turn off the third mouse button altogether. There are probably more.
Except multi language users who have to switch keyboard languages frequently. In some keyboard layouts extra characters are mapped to number row, so having extra numbers nearby saves more time than switching layouts. I also find numpad to be very useful when working with {favorite spreadsheet application}.
I never used a numpad on a keyboard, but recently have been experimenting with 36 key keyboard layouts, which basically require an embedded keypad triggered by a layer shift and I really like it.<p>I think it's relatively common on laptops via "numlock"? Worth checking out if you type a lot of numbers I think.
A significant advantage of a keyboard without numpad (particularly on a laptop) is that it's centered, instead of always having your hands left of center.