cluster munitions cover way bigger area. this makes a difference in several ways:

1. you don’t need to haul as many shells to the frontline in the first place, making entire logistics easier
2. you don’t wear out barrels as much, which makes artillery work for longer time
3. you cover entire area at once, taking enemy by surprise and denying them time needed to go for cover
4. submunitions are DPICM, which means that if a vehicle is hit from above by it, it can be penetrated (yes, even tanks) unless covered in ERA or such. in contrast, you need direct hit or almost direct hit of unitary projectile to disable armoured vehicle
5. it’s not one big boom, it’s lots of small booms, which means that some bomblets will fall into trenches. unitary airburst shells offer similar capability, but these are rather uncommon for some reason

disadvantage is price, but also small size of each bomblet. because of small size and need to manufacture them in vastly higher numbers there are some limitations of fuzing mechanism that make it fail more often than your everyday unitary artillery shell. this is known limitation that lead to withdrawal of cluster munitions in the first place, at least in some western countries, and also reason for development of M30A1 AW for GMLRS. this will be mitigated by humanitarian demining made easier to some degree by painting submuntions bright yellow.

one thing to note. cluster warheads are effective weapons, but have limitations. namely, western doctrine relies on rapid movement, and if you shell enemy positions with cluster artillery, you can’t safely advance before demining takes place, unless you are either advancing in armoured vehicles only or are willing to take these losses. this is the less shiny reason for putting cluster warheads out of production in the western militaries

Ukrainian drone operators are also using single submunitions, presumably from cluster bombs, as drone dropped ammunition (i've seen at least three separate videos of this). these things are well suited for this role and are used in vastly smaller numbers minimizing UXO issues in the future