A healthy economy will, in most cases, exhibit inflation. For most economies, it would take a concerted act by a central bank to force deflation in a normal, growing economy. People are making more, spending more. The government has to print more money to keep up, otherwise it will fall short of people's needs. Only in special circumstances does this not hold up.
> I don't see a benefit to prioritizing the interests of debtors over savers.
There's a huge benefit. We want to encourage economic activity over inactivity. Money in circulation is the very definition of economic activity. Money saved is the very definition of economic inactivity. Nobody borrows money unless they want to spend it, it makes no sense to borrow it just so you can keep it in the bank or under a mattress. Money borrowed is money invested.