One further comment I'd add...
With the EELF2k not blikin lights, the terminal and monitor and gets used
more as a result. With the Original ELF nothing but switches and lights.
I still pull mine out to play. Elk2k I don't use the switches but the leds
are useful at times to see loops.
Takes me back to Altair8800, hated the switches they made the fingers
hurt after entering the loader for the fifth time. But with new software
the leds would easily show it looping on the IO port address even if
it was not the actual port address, so patching to code for the available
hardware was easier. That was right up until a resident monitor, the
leds made it easy to see loops and tight sections of code but the
monitor with search for byte value made it faster to patch.
For me the experience is a thing that got old and the fingers remember
the pain. It also taught me that even simple software and a terminal
I could gain experience with the hardware and programming faster.
If you never used switches its interesting and maybe you should as
then you appreciate the value of a debug monitor brings. At the same
time switches and light gets one very close to the metal.
So the side effect is I have an Altair8800, CosmacELF, and a 8039 (8048/9)
simple low parts count machine like a ELF all with switches and lights.
I also have for over three decades the grandaddy of the front panel system
the PDP-8 which if anything had a nice switches that didn't cause pain.