If people want to do invasive injections that is their choice.

But why do that when oral will give the same results?
(when done with methyl form and correctly on an empty stomach).

The problem I have is that monthly injection. It seems that it may not provide enough for everyone equally.

I will also add... frequent injections (like some weight loss doctors do for celebrities) may damage tissue over time.
I recall the autopsy report of Anna Nicole Smith, who had severe scarring and fibrosis in her buttocks from frequent B12 injections.
They also found several bottles of 30ml B12 in her fridge. (forensics). I followed that case and her son's death previously closely because it seemed that both of them were drug related.

So what matters is to get tested periodically and see what your levels become with what you are doing.

Some people can do cyano fine. Others not. So with the low price and easy availability of methyl oral now, why do anything else? I try and find the most economical (this is for life for most people), non invasive non side effect methods to fix your issues adequately. Ego does not really enter into it...and online there tends to be a trend to push the "best" method. And for people, this may vary depending on personal genetics and other factors.

There is a huge placebo effect for all medications, and for some that might include a spiffy injection. Up to 70% of results can be due to belief! Also in Europe the European Union has blocked some OTC
medications, and injections would still be available by the doctors
there who may want control of this issue. Methyl B12 here is typically
obtained by injection from compounding pharmacies.