@Mario ******
I wonder why that is? A strange and useless rule. Besides, once the Lao consulates move to the e-visa, they'll have to rethink this whole thing, regarding conversions.
Having said that, in other jurisdictions using the e-visa system, it can be quite fast. Vietnam and Cambodia (especially Ho Chi Minh) can issue e-visas in as little as 48 hours (though they state the processing time is now 5 business days).