I play baritone ukuleles as well as tenor ukuleles. I think of baritones as ukuleles with a lower voice, not as guitars without the bass strings. Maybe that's because I play tenors with low G strings, so for me a "typical" ukulele sound is not reentrant. I think, like larger members of the violin family, baritones serve the important purpose of contributing a lower voice. In the Hawaiian music group in which I performed (before the lockdown), the baritone adds depth to, and fills out, the sound of a bunch of ukuleles playing together that are all tuned GCEA. It also makes this lower voice available to those of us who either can't or don't want to take on the challenge of the additional strings of a guitar.
I also play tenor guitars, which have an interesting history that relates to baritone ukuleles. They were developed when banjoes were losing favor to the sound of big bands. For tenor banjo players to get gigs, they began playing instruments that were tuned like tenor banjoes, so that tenor banjo players wouldn't have to learn new chord shapes, but sounded like guitars (that's where the "tenor" in tenor guitars comes from), so that the sound would fir in with the music of the period. The higher guitar-like voice of tenor guitars (without the two bass strings) became so popular that some guitarists began playing tenor guitars, retuning them to the highest-pitched strings of a guitar so that they wouldn't have to learn tenor banjo chord shapes. This DGBE tuning in tenor guitars was called Chicago tuning and appears to have influenced the tuning of baritone ukuleles.
I guess the point of the story of how tenor guitars developed is that for a very long time, musicians have understood the benefits of being able to offer the sound of a guitar without the lowest two strings. Baritnoe ukuleles sound different from guitars and they sound different from tenor/concert/soprano ukuleles. the fill a niche in the music spectrum. it's possible that those who dismiss baritone ukuleles by saying "I'll just play a guitar" don't see the need for an instrument that sounds like only the four highest-pitched strings of a guitar, but historically many people have recognized that need and the baritone ukulele fills it.