To be honest, it depends on how responsible a student is. I myself is a still a student who relies in Bitcoin to help me finance myself but I for once haven't forgot about my studies and had an average grade of B+. You should consult your students and approach them to give them some advice. It's not Bitcoin's fault but it was students entirely. 
and it depends to the teacher as well,since your all in crypto teacher and student,i think thats a great way to work in profiteering here,and work academics not unless your student is being getting greed in financial help of bitcoin,and they have no care in future but only in earning.thats what you need them to motivate.your the only person that can help them perform in crypto and school