Don’t forget that opaque blockchains can have invisible inflation. Transparent blockchains will always be worth more, as the user can verify that inflation has not occurred. This applies to grin as much as xmr.

Indeed that is one downside of hiding amounts, as shown in row "Fully auditable supply" in [1]. Finding out just one discrete log (log_G(H)) can collapse the whole system with undetectable inflation.

[1] https://phyro.github.io/grinvestigation/why_grin.html

In opaque blockchains, the mechanism that prevents inflation is the same mechanism that prevents double-spending. The user can verify that inflation has not occurred by running a monero node.

Everything considered, I don't think that the risk of a monero inflation bug is greater than a bitcoin inflation bug when you consider the complexity associated with scripting.