The reason is simply that ALL Thai embassies and consulates are moving to the eVisa system, a process that has been in progress since quite a few years already.
After other nearby Thai embassies (Hanoi, Phnom Penh) and consulates (Ho Chi Minh City) switched over to eVisa, the writing for the ones in Laos was on the wall.
You don't pay cash, you pay online when you apply. You are supposed to be located in the country where your application is being processed throughout the duration of the application process.
The multi-entry Non-O visa has been on its way out and isn't available via the eVisa system anywhere. So yes, they're clearly trying to push people who live in Thailand long-term towards getting 1-year extensions from immigration within Thailand.