My two cents worth.......
I dont feel that pine in general is very good scrolling wood but, I may be wrong. I know that it bloches real bad if you stain it even if you use shellac as a sealer first.
When things get as thin as 1/4" I think your best bet is plywood. Thinner stock of almost any wood tends to break if you have smaller areas cut into it. Popular wood is a bit better than pine and doesn't have as meny knots and hard spots as pine. It will still blotch if not coated with shellac first but, it is a hard wood and holds up somewhat better.
Now, let me qualify my statement about plywood. The stuff you get at the big box store can and will break as easily as solid wood so I would recomend spending the money for better "scrolling" ply that has more plys and usually doesn't have voids in it.
I recomend staying with 3/8" or 1/2" thick solid wood for most items. Now I will qualify that statement with...It depends on what your are cutting and how large it is.
OK so I got 3-1/2 cents in this reply...Sorry.
Rog