It made sense from the lessons of WW1. Especially the effectiveness of Belgian forts in the opening hours that basically single handedly derailed the operational timeline of Kaiser Bill's great willy waggle before it even started and delaying the Germans long enough for British and French forces to meet them at the Marne. Also Fort Vaux where a small garrison of old men, cripples and assorted ragtags managed to hold up the entire german advance in their sector for 6 days until they ran out of water.
>>64152508
The French really catch a break around Sedan.