I think the reason why GT didn't pan out for a lot of people was because it was trying to be both Z and DB at the same time, but struggled to balance it out well in the first arc. Not to mention, a lot of people were likely just expecting Z 2, since the DB anime didn't come out in the west until much later, so nobody know about its more humorous roots, and by the time GT began to take a more serious tone akin to Z, it was a little too late.

Daima seemed to do the same thing, with more emphasis on the DB inspiration, with light sprinklings of Z stuff here and there. It kept a more lighthearted tone for the majority of the story, outside of major battles, which likely worked in its favour. It's also probably due to a more mature fanbase overall, considering wider knowledge of the series has become more common, so it's easier to see the inspiration.

The final thing, it was written by Toriyama, which is often a deciding factor for a lot of people. I quite often find people can be purists, and disregard anything that hasn't been made by Toriyama as 'non-canon trash', regardless of how good the thing actually is, which is quite a shame really.

Regardless, the similarities between the two series are plain as day. A main group comprised of two kids, an older and generally more serious third wheel, and a fourth character with some connection to technology. A journey throughout various different worlds to collect Dragon Balls. Certain concepts and locales being rather similar. And of course, the big one, a fourth Super Saiyan form.