Cannot parse a year string with DateTime

[guilhermebodin]

Just came across this behavior and it seemed very odd, could this be a bug or is there a reason for not parsing it?

               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.10.0 (2023-12-25)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
|__/                   |

julia> using Dates

julia> Date("2000")
2000-01-01

julia> DateTime("2000")
ERROR: ArgumentError: Invalid DateTime string
Stacktrace:
 [1] parse(::Type{DateTime}, s::String, df::DateFormat{Symbol("yyyy-mm-dd\\THH:MM:SS.s"), Tuple{…}})
   @ Dates C:\Users\guilhermebodin\.julia\juliaup\julia-1.10.0+0.x64.w64.mingw32\share\julia\stdlib\v1.10\Dates\src\parse.jl:278
 [2] DateTime
   @ Dates C:\Users\guilhermebodin\.julia\juliaup\julia-1.10.0+0.x64.w64.mingw32\share\julia\stdlib\v1.10\Dates\src\io.jl:568 [inlined]
 [3] DateTime(dt::String)
   @ Dates C:\Users\guilhermebodin\.julia\juliaup\julia-1.10.0+0.x64.w64.mingw32\share\julia\stdlib\v1.10\Dates\src\io.jl:568
 [4] top-level scope
   @ REPL[3]:1
Some type information was truncated. Use `show(err)` to see complete types.

[guilhermebodin]

For reference, @quinnj posted on Slack that this snippet works

julia> parse(DateTime, "2000", dateformat"yyyy-mm-dd\\THH:MM:SS.s")
2000-01-01T00:00:00

but the simpler syntax version does not.