I just bought this the other day to setup a VPN to guard the IPMI interface in a 2U server I could cheaply house in some otherwise unmanaged rackspace. It's a pretty nifty piece of kit, but I still have to get better at understanding RouterOS.
I think the crucial flaw here for the IPMI/BMC access use case is the fact that the card requires the server to be powered on to function. So if you accidentally turn the server off it’s game over for remote access.
Then all you need is a remotely-operated power outlet, which is pretty standard for colos nowadays. Toggling the power outlet is as good as a human driving out there and poking the stupid ACPI power-on button.