This is because of the new interface which we are having to learn.
The old method of writing blog posts used to work, but recently Google (who run Blogger/Blogspot) have introduced a new interface which doesn't work.I assume that the new interface is designed by people who write web pages, and that is all they do.
They spend all day every day writing the new interface, using it, getting it to work for them without it ever entering their heads that people who blog also do other stuff - like have families, jobs, play sport, do the stuff they blog about....
If I had all my working life to learn the new interface and the new way of doing things it wouldn't worry me (as long as it worked, which it so patently doesn't).
But I don't have that time. I want to go in, type my new blog entry - quickly - and have it appear when I want it to appear, looking like how I want it.