There was metal under the decks of the Cruisers-
Mogami had her Linolium ripped out on her last
mission, but another source claims it was still in
place.(at least on the AA deck.)

Fuso had her Linolium ripped off her quarter deck, for
her last mission, as did Yamashiro. There was wood
underneath.

The Japanese heavy cruisers were very much overweight,
but that was because of attempting to do too much on
too little of a displacement. The pre- treaty Light
Cruisers also had linolium decking as well- they were
all well within their weight limits. It's probabably
not due to weight issues.

There was a shortage of wood in Japan- Most Japanese
rifles have 2 peice stocks for that reason... but
again, either metal or wood was under the linolium.
I think you are asking the right question- why did
other navies persist in using wood?
Wooden decks are considerably cooler than steel ones-
could that be the reason?

*****************************
1 Wood decks heavy
2 Linoleum less expensive
3 Wood hard to come by in Japan?
A better question is why other nations used hardwood
decks. Maybe a carry over from sailing ship days but
how much wood do you see on modern warships?
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There are two theories, both which came from IJN
survivors. Theory one, and true to an extent was that
Linolium was an excellent no skid material. Secondly,
the Linoleum kept below decks cool during warm times
and warm during the winter.

These theories are anecdotal, so I am not sure how
accurate it is. One thing that is sure, Linolum burns
like crazy- pics of Japansese Cruisers on fire show
the decks literally blazing away.