Do you have a product you're trying to sell? Is there any point in showing it and bragging about it to people who aren't interested? Very few people want life sized inflatable dragons; but the ones that do could be loyal readers and a fun blog community.
Do you just want to share your admiration of a subject you love? Then don't worry about being big, worry about being good; and enjoying the things you're writing for rather than doing things seeking attention. Many "fandoms" have a high proportion of "zero sum" thinkers who cheerfully attack anything not theirs, anyway; so seeking feedback is of debatable value in some fields.
you wouldn't have to work hard to promote it.
Sorry, I lost you. Why is this one easy to promote ?
People will fall over themselves to be the first to post a link to a new post on that blog to HN because they know they could get 100-500 karma points just like that.
https://news.ycombinator.com/from?site=righto.com
The "quality" of that blog is multifold.
On one hand if you lived in the 1980s and loved the music the Yamaha DX7 he is talking about now makes you feel pangs of nostalgia. Even if you knew nothing about electronics you might share that post with your music-loving friends. Very few people know a lot about making microchips but most people find his die photos are pretty. People at very different levels of knowledge about electronics, math and similar things will all get something out of his posts.
Contrast that to the average blog which really is not of interest to anybody at all. For instance there was a guy who was complaining that his blog got "banned" on hacker news. He was writing pithy and worthless posts that were barely worthy of a tweet. Stuff like "I was suffering from anxiety and I feel better after meditating for three minutes a day". (Yeah right...)
A lot of people write blog posts that frankly aren't interesting to anybody and they struggle to "promote" their blogs... They could spend $1000's of money and many many hours promoting their blogs and they are just digging themselves a hole.
So quality content is the foundation.