Old decks get slippery when from organic material and worse with wax based sealers. Then there is the cosmetic blemish of aging with black stains from slow drying areas. Stain looks great but slows down the drying out process which aggravates spots where water collects whereas as unfinished dries the quickest but turns grey from UV.
Appearance will vary greatly with porosity and density of wood. I find staining to be a short term solution with accumulating stain over the years required due to UV effects. Pressurized water removal is slow but regarding your question ... adhesion after a days of sun drying is not a problem. Pigment fading under UV is a problem as is black fungal growth, which I presume took many man-days of sanding.
Stain also makes the surface hotter for bare feet. My preference is unfinished which turns stays grey and can be restored every few years by bleach or better pool chlorine dissolved in water applied with a roller on a broom stock then a stiff floor brush and rinse with a hose. Chlorine will evaporate in a day or so and wood will look as good as new with very little surface wood removed. This removes any black, green or other stains and makes sanding unnecessary unless you have slivers. It is also 5x faster than sanding. It will turn grey quickly and stay that way, dry faster and be cool under the hot sun.