The fact that the protein is synthesised by your own cells is irrelevant.

Not necessarily though. The spike proteins aren't attached to anything, so the immune system may begin to recognize the back side of the spike protein as a threat, a side of the protein which would normally be attached to the virus and thus not ID'd by the immune system.

Furthermore these disembodied spike proteins share some overlap in shape with a protein in the placenta, and it's beginning to look like it's causing miscarriages on occasion because of this, which is why they don't recommend it for pregnant women.

And lastly the immune system notes the shape of the protein and what it's attached to, which is partly why traditional vaccines include the entire virus. If the spike proteins are poking out the membrane of your own cells, on occasion the immune system may begin to ID your own cells as being hostile because it is associated with the spikes, thus creating an auto-immune disorder in some people.

So that is 3 examples of false identification potentialities that could be avoided with a traditional whole-virus vaccine.

It's not all bad of course, and it is a breakthrough technology no doubt, but these types of problems (and the large number of people having adverse reactions) should not be waved aside. A long time doctor friend of mine just got his second dose of the mRNA vaccine as required by work, and afterword he said "I don't want to discourage anyone from getting the vaccine, but if I had known the adverse reactions would be this severe I would've had more caution going in to it."

I think these concerns need to be taken very seriously, especially considering the companies who manufacture these vaccines have zero liability or fault as per federal law (as per the National Vaccine Injury Compensation Program), so the companies unfortunately aren't very incentivized to spend a lot of time researching the side affects, and are instead more concerned about rushing it to market as quickly as possible. These profit and liability motivations make the quality of the research a bit more questionable, in addition to the technological/biological problems that are presenting themselves with this technology.

My deepest fear is that the cure is worse than the disease. I sincerely hope that is not the case here. But I guess we will find out over the next few years. Phase III FDA testing was partially skipped in order to bring it to market faster. Which is dangerous for a typical vaccine, but absolutely frightening to see these safety barriers bypassed for an entirely new technology of mRNA based vaccines, that manufacturers also have no liability for, and is proving to have a large proportion of adverse reactions compared to typical vaccines. And furthermore I see these sorts of concerns frequently brushed aside by the media and even the medical and scientific communities, which is unnerving.

But I am hopeful about the mRNA technology in the long-term, and the thousands of potential disease-curing applications, I just think this has been rushed and we don't fully understand this technology yet, so I'm going to wait at least a few years for the evidence to come in and the dust to settle.