Does Russian currency devaluing actually mean much?

At a guess it'd probably make people want to spend less if those value reductions impact the cost of services there.

If Russian currency isn't being used much in the external market, maybe that's why. If yuan and rupees are the main currencies for buying oil, Russia could be holding those currencies instead or exchanging them for cash equivelants.

A lot of devaluations in war are a result of other things such as currency counterfeiting and talent fleeing abroad to a safer country.