MySQL not having a proper type to express time spans seems like a fault to me, and "poor design". Of course you can just use an integer for it, but that is a slippery slope, in the end you'll find that you can use strings or byte arrays for everything and you end up with no type system at all.
The surprise here is not that the type has limits but that they are so awkward and that there is no better strongly-typed alternative.
The surprise here is not that the type has limits but that they are so awkward and that there is no better strongly-typed alternative.