Travel time is character time... it's an opportunity to have conversations between characters that reveal things about themselves or their relationships to other characters. Lots of mundane crap happens during traveling, especially if you're being very realistic about it. There's time on the road, but also time setting up or breaking down camp, time spent gathering or preparing foods, time spent caring for equipment or mounts (horses have a whole routine you need to go through every time you start and stop for a decent period of time), time spent on watch while the others sleep.
Not only are these times you can build up on the characters through their interactions and conversations, but you can also slip in world-building details when describing the actions they perform as they interact. If they're gather food or caring for a mount, that's a time for some flora/fauna world detail. If they're caring for equipment, that's time for technology and crafting detail, and so forth.
If you haven't got anything to say between larger plot points and don't need to develop the characters or world further, then there's no real need to show anything happening as they travel. Sometimes it's enough to say they went from here to there, and it took this long, and nothing much happened. But honestly, if you think about characters spending much time with each other it's hard not to envision ways in which their interactions and conversations reveal things about themselves to each other and to the reader.