The definitive explanation of the pickup timer is even more simple.
This timer sets the time interval during which the bot will NOT worry about collectable items in its field of view.
This timer is periodical. For example, if you set it to 30 seconds, the bot will sample its field of view and check for items at 30s, 1min, 1min30, 2min, 2min30, etc..., but it will ignore all items in between.
Hence if your bot sees an AWP (or a bomb) lying on the ground at 35 seconds and runs past it at 50 seconds, the bot won't even have noticed it.
If however you set this timer to 5 seconds, the bot will see the item at 35 seconds, and will start running towards it at 40 seconds.
Nice avatar KWo btw