The current approach is more conservative. What would be the advantage of this proposal?

It's only conservative as long as the maximum value we allow to be encoded exceeds what's relevant for routing decisions.#2987 is an example where this strategy introduces artificial weight limits that are far lower than what is actually tagged in OSM, while the encoded value is still in the range of values relevant to truck routing. Searching for a route with a 26t truck in my case.

Ideally, the EV should be able to cover all "sane" values (see#2989), so that we can ignore values that are either tagging errors like kilograms instead of tonnes, or are far too high for our intended use case.

For example, thisway has a maximum weight limit of 120t. In practice, this is so high that it's irrelevant for any normal vehicle. But by limiting it to the maximum storage value of the EV, we create an artificial limit within the range of values relevant to large trucks.