- Sonic Pi has (we believe
) an amazingly low learning curve, expecting neither music training nor coding experience, being designed in the beginning specifically to introduce computing to school children - It’s easy to share your compositions to be viewed/read by others - plain text, rather than some obscure unreadable format
- Just the fact that it introduces you to computing ideas (sometimes by stealth too, like concurrency with live_loops!)
- The fact that syntax and logic errors in Sonic Pi script are laid bare in the errors panel, and are often easy to produce just by typing slightly wrong code, as opposed to DAWs being highly engineered to remove as much chance as possible of errors occurring, or maybe producing bland errors. I’m reminded of a ‘philosophy’ of sorts in much of the live coding community: errors shouldn’t be scary - they should be embraced
like Sam himself mentions: there are no mistakes, only opportunities! (Related to this: Sonic Pi is great in that a lot of time when they do occur, errors are not fatal for the entire composition/performance, but might just stop one or two threads/live_loops, which can be corrected on the fly 
)
There are a few other things that Sonic Pi has that may be considered an advantage over a DAW in certain contexts - some of these I could probably steal from the great points made by folks such as @xavierriley and @Eli over at DAWs vs Coding Music. (Whether applicable to an educational environment or not I guess could differ depending on the situation, but: )
- simple text editor interface vs GUI densely packed with controls
- text interface with commands that are built on the basis of actual language, which can potentially be more self-descriptive than knobs and buttons
- interfaces governed by menus and buttons, vs ‘menus and buttons in your mind’
- (perhaps related) flexibility to do complex, large-scale or non-standard things with a bit of code, vs bending or wading through a set workflow
- (related again) many ways to do a thing, rather than only perhaps a small few ways of doing a thing, according to the ideas of a DAW or the general ‘music community’ at large