I think it’s not a problem if all fields are always available in all other Views (besides Entity Views), because we already have the ability to customize those views and exclude certain fields.
But this ability would be very useful in Entity Views - if we could conditionally display Entity View fields, customized for each entity, based on the value of a single-select field, that would be a good solution to this issue.
Perhaps we could have the ability to add to each field in a Type, a formula, to determine for each entity, whether the field should visible in its Entity View.