- The Raspberry Pi is one of the better technical solutions. It is relatively low cost, low power, and is fairly representative of how the Macintosh SE would get on ethernet networks back in the day. (In many cases a more powerful computer would serve as a bridge between LocalTalk and ethernet networks.)
- Ethernet cards for the SE are rather uncommon since most SE's used LocalTalk for file and printer sharing. PDS cards were more-or-less specific to a model of Macintosh, so the option of sticking in a card intended for later models is not an option. SCSI-to-ethernet bridges are only an option if you find one with the drivers, since the drivers are virtually impossible to find after the fact.
I will admit to being a bit disappointed by this article. I was hoping for something more along the lines of interfacing an SE to the Raspberry Pi's internal UART since that would take a bit more skill, though not an absurd amount of skill. On the other hand, it is a demonstration of getting an archaic SE online is more about creativity than ingenuity. That's important for many of the people who pursue vintage computers as a hobby since they don't necessarily have the electronics background to design anything more sophisticated.
I just saw a video by a vintage computer collector who had one of those Ethernet-Localtalk bridges, then realized I used to own one!
This is becoming a horrific meme. You didn't read the article, made an assumption and reverted to this cliché