strange that nobody evokes the case of a deployment on solana? ^^
to come back to the main question multichain deployment ... it is useful to also ask the questions of what populations do you want indirectly targeted and what "currencies" or value do you want to add to the cash flow? MIM is indeed a solution that develops very quickly and in a cross-chain way, it is collateralized with ETH (if I'm not mistaken) which makes it a good complement / equivalent / competitor of DAI (from a theoretical point of view ) ...
to bounce back from the Dotsama proposals mentioned above, they offer different types of target populations with several different currencies all interoperable by design ...
moonriver is carried by the US / EU market, and soon linked to the Kusd (and Ausd) of karura / acala backed by dot / kusama
shiden is a hub which is about to host Standard protocol (usd) and JPYC (yen) ...
and while all of this is in the works, the expansion and use cases should be operational in early 2022 ...
by extrapolation, if KLIMA decided to deploy on Polygon, it was probably for economic reasons (costs), energetics and for the strong Indian community, as well as future project development in India (speculation).
why not do the same by targeting typical populations directly correlated with a technology and a typical value?
all Ohmies, but with their own peculiarities ...
not sure that it is very clear