Yes, but imagine you worked online all year. You'd have to do your taxes, and maybe the authorities could get funny that you work and don't have the right visa. Maybe I'm over-thinking it, but strange things can happen in Thailand when someone wants to make a point.
Oh ok. Does it say "work prohibited"? It seems some do, and some don't. I am guessing that a lot of people who spend five years in Thailand, or even 2.5, will need to work to fund their lives. I'm just confused about this. It's not clear.
I've followed this topic for many years. Technically, you are not supposed to work online, but they don't really know how to enforce it. The DTV is a way to make things more acceptable. Sure, there haven't been busts, although some dudes teaching English online were once busted, and cops once shutdown a co-working space in Chiang Mai.
That's not strictly true. All work is illegal without a permit, but since the world modernized, Thailand didn't really have laws about online work. Now things are changing, and people will be we expected to have some kind of work visa, hence this new visa.