I for one in particular was the one complaining about the memory card slot they took away. You loose that extra expansion and I knew once I upgrade to a new phone, it will be a problem transferring stuff. For me it was all bad,and also I thought it is the one thing that still keep me buying samsung. I made my decision and got the samsung S21 ultra. My previous S10 plus had 128 gb and this one had 256 gb ,so the extra 100 odd gb was a bonus ,as my memory card was also just 64 gb,so no comprimise. Two weeks down the line,and it really starts to make sense,for this reasons: Faster accessing of my files,because of ufs 3.1, it's amazingly fast accessing files,the next point is, samsung smart switch transferred all my stuff,even from my old memory card to the new phone,so no fuss. Another thing which makes sense is not having to manage two file systems,internal and external. I occasionally encountered problems with the memory card not reading after ejecting and inserting my sim card. What I also realised with the s10 is that you actually need to buy a good sd card,normally the expensive ones are better,saves you on malfunctioning of your phone. The only downside is with water damage or some malfunction you might loose everything,so to back up on the cloud now and then might be a good idea. A lot of us also are making use of youtube music or spotify,so we don't really loose music when changing devices,as your purchases and playlists stays in the cloud and we just download music from these providers to listen it offline on our devices. Youtube music and spotify will not be more rha R100 subscribtion a month anyways. I actually would recomend buying the samsung S21 ultra 512 gb once it's available in south africa,a lot more bang for your buck. You get double the memory and 16 gig ram instead of 12 gig ram. For like a R1000 more. You see extra memory is a lot cheaper with samsung than our cupertino friends,as their devices goes up for about R3000 to R5000 more if you need extra memory,the apple fanboys might slaughter me,but it is what it is. So there are quite a few good reasons and samsung nailed it with a lot of benefits.
