if you want a mikrotik, buy a mikrotik hardware 1U router, despite the many issues with them the one thing they do have going for them are low power consumption and small space use. an actual ccr2004 1U box is not that large and can be mounted almost anywhere.

In your own rack, you would do exactly that. But if you paying per U in colo, this card can save you one slot.

If you have enough traffic to need multiple SFP28 interfaces in colo and can't pay $150-250/mo extra to put in place a real hardware router, or stop paying by the 1U increment and get 1/4, 1/3 or 1/2 of of a cabinet, priorities and risk tolerance are misaligned in my opinion.

if you have >10Gbps traffic flows and are putting the router and other hosting environment/linux things all together in one 1U piece of hardware as a single x86-64 server, that's a "too many eggs in one basket" problem.

also worth noting that many colo/hosting ISPs won't offer 25GbE circuits on SFP28 anyways, you can buy either a 10GbE transit link or 100GbE, or maybe 2x10GbE bundled together in a 802.3ad or similar.

In this case, I was thinking about moving a currently half a rack worth of equipment from premises to colo, as the (internal) users are mostly on WFH anyway. They would not generate 1 Gbps of external traffic, not even in spikes. Currently, as it is, it makes more sense to stay on premises, but if some increase of density happened, it could make some sense.

However, it is not going to happen, it would be somewhere at bottom with priority. It was just an exercise, what could be done.

Maybe I'm dense, but wouldn't that solution still use 1U more space than the PCIe card mentioned in TFA?