I've got a few old Mileater diaries which I very occasionally look at either for reference purposes or for nostalgia.
I stopped entering Mileater when I started entering my rides on a spreadsheet- and now I use RwGPS.
The electronic versions lack the ability to include witty asides and little sketches (!) - at least easily, and I feel they are less permanent somehow than paper.
If I really, really wanted to continue with paper records I'd buy a notebook from a shop and do it that way. If AUK (we) want to continue with Mileater then electronic submission is probably the way to go, either that or a self-certified end-of-year total submission- which feels a bit 'dry'.
On the other hand the question remains- what is the purpose of Mileater? I doubt it motivates, there's only one trophy, and you don't need it for nostalgia or records.
I'd suggest that if Mileater is to continue then there needs to be a number of different awards apart from greatest annual mileage. For example - 'highest mileage outside UK', 'greatest climbing height', youngest/oldest/opposite sex, tricycle/down-wrong/hand cycle/eliptigo etc, 'highest average ride length' as random top-of-my-head thoughts.