There's logic to this... Most exchanges have most of their funds offline, and only a small portion on their servers (to reduce losses in case of a hack).
When volumes go up, the servers run out of money, and everything grinds to a halt till humans intervene.
The humans typically want to do a lot of checks they aren't being tricked into refilling the online wallet too. Those checks are usually manual and take time.
When volumes go up, the servers run out of money, and everything grinds to a halt till humans intervene.
The humans typically want to do a lot of checks they aren't being tricked into refilling the online wallet too. Those checks are usually manual and take time.