That doesnt seem to be the case. The spec sheets from the French, German and italian press releases make no reference of MST. The Dutch one does list MST, as does the Polish, Russian and Indian news release.
The S21 phones sold in the United States are in the group that does not have MST. Phones offered in the UK do have it. Is this due to the fact that of the different chipsets (Snapdragon in the United States, Exynos in Europe)?
Some Galaxy S21, S21+ and S21 Ultra units do not support MST for Samsung Pay. It appears like availability of the feature differs by country– some get it, others do not, and not in a method that makes much sense.
MST enables the phone to deal with point of sale terminals that only support old-school magnetic stripe cards. This is a huge deal in the United States where such terminals are quite typical, less so in areas where NFC terminals are plentiful.
Here is Samsungs declaration on the matter when asked by XDA:
Due to the quick adoption of near field communication (NFC) technology by consumers and services, starting with devices launched in 2021, Samsung Pay will focus its assistance on NFC transactions, throughout the Galaxy portfolio. While future devices will no longer consist of magnetic stripe technology (MST), clients with previous, compatible Galaxy devices will have the ability to continue using Samsung Pay, including MST.
MST was presented with the Galaxy S6 in 2015 and has actually been a staple of high-end Galaxys since. Now it has one foot out the door.
The S21 phones offered in the US are in the group that does not have MST. The spec sheets from the French, Italian and German press releases make no mention of MST. The Dutch one does list MST, as does the Polish, Indian and russian press releases.