> because a user has to be allowed to log into a new device (if they lose their old one)

You can solve for that by having short validity of the offline tokens on device and having that equal the cool-off period for reclaiming those funds when new device is provisioned. If I had ₹100 unspent tokens in my offline capable device that I lost, and got a new device provisioned the same day, then that ₹100 will show up in my account and be available to load on my device only after, say 7 days, of cooling-off period. In those 7 days, if someone who found your device could spend it and if so you lose it. If you know you are likely to be offline only sporadically for few hours and not for days, you can reduce the validity (and hence cooling-off period) significantly to just 12 or 24 hours.