Lots of good high-quality info here guys, I'm enjoying reading this thread -- it's a real gem, thanks!
That's pretty much top speed of the Gen 2 Mobile Connector which tops out at 32A -- if 30A is not a typo, you're not really missing much with 2 fewer amps. BTW, 30A would be 7.2kW (while the full 32A is 7.7kW). On 32A, which is pretty much the same as 30A, the Model 3 Long Range's battery pack could be fully charged from 0% -> 100% (not that you'd ever do that, but in theory) in 13 hours. There is absolutely no need for anything more than this, outside of some very specific edge cases (example: someone who drives 150 miles, comes home and only stays for a limited amount of time like 3 hours, then needs to drive another 100 miles roundtrip; this is of course highly atypical). 48A via HPWC is 50% faster (11.5kW) but wholly unnecessary for a Model 3, although it may make some sense for people with S/X (which are less energy efficient) who have considerably longer than average daily commutes. There is also the Corded Mobile Connector which splits the difference and will do 40A (9.6kW) via a NEMA 14-50 (which should always be on a 50A breaker).
Just a data point, my house didn't have space on the main panel either and the Tesla-recommended electrician (who did an amazing job and became a friend) had to install a subpanel to which he moved a couple of the circuits (breakers) and installed the 50A for the NEMA 14-50. This cost all of $600. For me personally I would never ever go 120V unless there is no way to make a 240V happen. Just the installation alone is much more sturdy, I just feel uncomfortable running 1,440W for extended periods of time on a regular outlet plug (that's not behind a counter like a microwave is -- but microwaves are usually less than 1.4kW, and they don't run overnight). I have young children so this is a bigger concern for me, but still, compared to how sturdy a NEMA 14-50 240V install is, the safety aspect alone is worth it (although I could not live with the idea of the slowness of charging at 1.4kW for any extended amount of time). The 240V is literally brand new cable rated to take lots of juice, run thru metal tubing directly from the main panel; this is vs running 1.4kW for extended periods of time over existing wiring inside the wall from whenever the house was built.
Here's last night's charge on 240V @ 32A -- this is typical of what's needed to recoup the daily commute on my wife's LR AWD, which averages 45 miles but uses up 60-65
rated miles (due to various losses -- and these will increase as temps drop, it's still warm here in Dallas)
Voltage at the scheduled start of 4:30 AM at our house is actually a bit higher and we charge at around 7.8kW. It still takes 2 hours+ to recoup, but a nice benefit is that, as mentioned previously, when it is really cold (really cold for us, for example it was 29F a week ago and that was basically the end of the world in my mind), charging at a decent pace like this will warm up the battery pack in the ~2 hours it takes to recup, and you leave the house with a warm pack. Maybe you get the same warmup from charging the entire night at 1.4kW, but as temps get lower you probably don't want to rely on the at-the-limit charging solution. And remember, you always have the flexibility to drop the amps to increase the charge if temps are so low that you want it to charge longer (time-wise), for example I can just select 16A and it will charge at 3.8kW which will double the charge time for those extra cold nights (not an issue where we live, but could be for others in more northern climates).
My concerns are exacerbated by having young children, I would not feel comfortable with taking the whole/most of the night to recup our average commute. Let's say there is a power outage, I want to be able to charge my car up relatively quick when the power comes back on (I lived in South Florida for a decade and still remember the abnormally high number of weather-related power outages). To top it all off, we had two Model 3s (I sold my P3D+)
[edit]P.S. Oh, and it looks like I'll be getting a CyberTruck, and I ain't charging that bad boy on 120V, no sir
But seriously, the reason I mention this is because installing a NEMA 14-50 can add value to a dwelling, either your property or someone else's that you rent, especially as EV adoption increases. The 14-50 has the advantage of being a standard, so doesn't lock you in the Tesla ecosystem, which for potentially adding value to a house is a no brainer (over an HPWC, which would require buyer to be a Tesla owner).