11 year veteran here, this event is awesome.

Originally posted by jaxjace: Really made something special here gaijin, really love the dynamic of AI infantry, it adds a lot to the game and I hope someday to see them implemented, they add a lot to immersion and make for a more well rounded dynamic experience.
The WW1 Tanks and aircraft are chefs kiss, the fact that we get to keep all the ground vehicles is a very welcome addition.

Glad you like it!

Originally posted by Gullideggel ツ: The infantry does anything?
I didn't even really notice them by now.
They are there and run around, sometimes (germans more then the others) but they didn't seem to do anything battlewise.

Yep, as mentioned in the news:

AI infantry roam the trenches and are a target while in your tank and plane. The British and German soldiers wear authentic uniforms from the time period and also charge into no man’s land. They can fire back at you and throw grenades, so watch out! Taking out one AI infantry will yield 5 mission points, up to a maximum of 500 mission points per battle (100 soldiers), helping to contribute to stage tasks.

https://steamcommunity.com/games/236390/announcements/detail/547856738465875902