32x32 has twice the size of 16x16 and the amount of pixels to square.
You could say that a 32x32 tile with a similar (complex) style is about 3 times as much work as a 16x16 tile.
Work for designing the tiles is for 32x32 also a little bit increased (slightly but nonetheless).
Means if you want to hire a freelancer making smaller tiles will greatly reduce costs or you can get ou tmore content with the same budget.
If you are the artist, try both approaches and look what's working better with your game idea.
The biggest difference will always be how a single pixel will be percepted.
Since you always will have to upscale pixel art (at least to 200%, for 16x16 even up to 400% or bigger) it could look odd if a single pixel takes up too much space.
for 32x32 tile a single pixel ill appear twice as small as with a 16x16 tile.
Or if you want to have something heavily detailled it might be impossible to pull it off with 16x16 tiles.
Or if your style features smooth lines it's better to go with a bigger resolution because you have more space for AA.
