In article , Tim Watts
wrote:

Perhaps in the early days when super high res eye pieces and back
displays were infeasible, it made sense. But now Panasonic can stick a
hi res display into an eyepiece and on the back, it's all a bit irrelevant.

except when it isn't.

an electronic viewfinder will never be as fast as optical. the
electronics adds latency. it may be 'good enough' in most cases, but
not all.

Not to mention these days, you want the electronics seeing the image all
the time for continuous tracking of various attributes (focus, exposure etc)

slrs do exactly that, long before there was digital.