"Easier to distribute" is a misnomer. "can be distributed using existing infrastructure" is more accurate.

Al Jazeera

The Pfizer-BioNTech vaccine must be shipped and stored at -70 degrees Celsius (-94 degrees Fahrenheit) – Arctic winter temperatures – and can be stored for up to five days at standard refrigerator temperatures or for up to 15 days in a thermal shipping box.

Moderna’s vaccine has an advantage in that area because it expects its vaccine to be stable at normal fridge temperatures of 2-8C (36-48F) for 30 days and it can be stored for up to six months at -20C (-4F).

It will not surprise anyone to discover that vaccine storage is an FDA-defined and regulated practice. There are entire categories of medical equipment for this. If you have vaccines, you buy vaccine fridges. Here's ours.

We are a part of the CDC's Vaccines for Children Program, which is a nice switch from LA where it was all about seminars to teach people how to get their unvaccinated child through life. This basically means the CDC fronts us tens of thousands of dollars worth of vaccines in exchange for our storing them in a controlled environment. That controlled environment is allowed a degree of deviation and if it goes out more than five(ten?) degrees it's a sentinel event - we have to log it, report it, toss the vaccines and hope we still get to play. The CDC can demand to see our logs at any time - we have to write down what the temperature is twice a day and report it every two weeks. As a consequence vaccine fridges have all sorts of alarms. Ours has two thermometers connected to the Internet, the whole mess on a battery backup that shoots me an email if things get more than a degree and a half out of pocket (opening the door raises stuff half a degree - in other words, I get "the door is ajar OH SHIT RUN" emails). It will not surprise you to discover that there are two vaccine storage temperatures: 4-ish and -20ish. Thus, if we wished to distribute Moderna's vaccine, we would just... put it in the fridge.

Pfizer's, on the other hand, likes to live ten degrees warmer than dry ice. Not quite cryogenic temperature, but hella colder than our fridge goes. Sanyo Medicools can't go colder than 35 below. We didn't do any comparison shopping on minimum temperatures but I am unaware of any other vaccines that require "dry ice plus ten" storage so I reckon other fridges are in a similar zone. There's an entire industry arrayed around dry ice storage and transportation; none of it is powered. I'm guessing that Pfizer is expecting everyone to fly foam coolers full of dry ice with RFID temp loggers around and accomplish vaccination via Fedex. Moderna, on the other hand, has created just another vaccine.