MSFFor some it's a Personal preference which isn't a great reason but definitely one that people care about.
Apart from that though one I can think of is better security. If your device is stolen a physical sim can be removed and stop the device from being tracked or found an esim is integrated into the device so cannot be removed.
Another reason is physical Sims can degrade or become damaged over time any issues regarding this is negated by ESims.
Both of these particularly the second one are niche but are reasons people would prefer Esim technology to physical Sims, there's also the possibility that down the line apple and other manufacturers will do awa with the Sim slot like they did with the headphone jack, apples already done this in America so not impossible for this to spread.
Personally I'd love for them to have ESims but it's not a dealbreaker for me with Smarty. It's not really a need but definitely a nice to have at least in my case.