mDNS repeater feature

I just wanted my guest network to be able to connect to the chromecast on the main network while being able to rate limit the whole guest network by simple queues, this might not be the right way but it was the easiest way for me to do it, I also wanted to setup a network only for IoT devices with no internet access, but further diving into this has only brought me across jank solutions.

I am perplexed by the hesitation to have mDNS by mikrotik (just looking on the forums there are multiple threads of such discussions)

Frankly I can’t comprehend the replies by the staff on this thread, and some of the replies are just fear-based rather than factual, and no examples given based on real-world scenarios.
FE;
How will having an mDNS server make these devices be able to access the internet? Unless your devices have already been compromised that doesn’t sound right! Actually it sounds very paranoid, being scared of something on the small chance that it might happen? Then why connect to the internet at all?

And let’s say even if the IoT devices were able to query local devices through mDNS how will they get internet access if the network they’re on is unable to?

So far the only solution I could find was having to buy a pi just to be able to run an mDNS server, as chronicled here,
http://forum.mikrotik.com/t/setting-up-avahi-reflector-in-mikrotik/139370/1
This actually hurt reading, the poor guy spending months on what should be plug and play tbh.
Anyway, it has been a tiring day and I’m just more frustrated that the solution to such a simple problem has not been implemented despite so many threads on the forum about this very issue