you can purchase Hubbell 14-50 at an electrical distributor for 45 bucksWe have a different opinion of what constitutes an "expensive charging device outdoors" - I'd call a $350 wall connector very inexpensive. If the vehicle is often stored outdoors why would I have a charger indoors, needing a cord to run through a door or window?
$300 is very inexpensive for an installation, normally the GFCI breaker is over $100 alone not to mention the other materials needed. Perhaps your install was much cheaper than the average install is. The MC is worth a couple hundred dollars regardless if you got it free or pay for it. A WC is very similarly priced or $100 more. There is most likely a slightly higher cost to most buyers installing an 14-50 outlet with a MC than a WC, and resulting in an inferior product. Perhaps your case it is cheaper or you are using an old electrical code that doesn't have GFCI protection, in which case your install is also less safe. Of course you and any homeowner is fine to use whatever option you want, but I can think of extremely few cases it makes sense to recommend someone install a MC over a WC.
as well, the same electrical distributor sells a 60A GFCI breaker for 65.
I'm in SoCAL. My electrician charged 225 for install including wire run, which was less than 8 feet to the panel including panel drop length.
of course, all this was just before the EV subsidies by Edison and the Feds began. Now, electricians know 700 is the subsidy and that's what they charge.