BTU vs XEU

[Shazzkid]

So I've recently learned about these 2 codes.

I know both are UK csc codes for unbranded/unlocked/sim free devices. 

BTU is for phones direct from Samsung

XEU is for phones from a reseller (such as carphone warehouse)

But why would Samsung need to release 2 firmware versions if they are the same? There seems to be some differences since on the XDA forums, a lot of people want to flash from XEU to BTU, but no reasoning given, and no one can agree which gets updates first. 

Anyone have any additional information related to this, anything at all? 

[Robbie-35]

your right btu the phones come direct from Samsung xeu the phones come from carphone warehouse etc they only difference is the btu devices usually get the update first and the xeu it's for UK and Ireland where btu is just the uk

[WelshPaul]

My S21 Ultra BTU device came from Amazon. My old S10+ XEU came from Carphone Warehouse and I never experienced any delays in receiving firmware updates, they hit the phone as soon as users started posting about updates on the Samsung community.