WW1 (and for that matter WW2) gaming in 10mm encourages people to deploy a significant artillery park off board. Well we've got a great range of guns and adequate numbers of gun crews to produce mini-dioramas of such artillery support but what we lack is ammunition. Virtually any picture of artillery in actions shows vast piles of shells lying around - both fired and waiting to be fired. I think you'd get by with one pack of field artillery shells and one pack of heavy artillery shells. Such an item would also be a logical add on to the Trench railway system.
Yes, these would be very useful.
Perhaps with some slightly smaller boxes than the ones in the German WWII range.
But you just know that some smart alek is going to look at your painstakingly built diorama and proclaim "Why on earth do you have what are clearly 105mm shells placed next to your 4.5" gun?" . . .
Heresy maybe but Irregular produce shells in their 10mm WWI range. I used these in my FPW C19th artillery fort ie. with Pendraken figures, equipment and scenery.
I would also vote for these, maybe several different sizes and maybe a few open showing some shells
Take care
Andy