The time aspect is seasons, most plants die off over the winter.
Why would you want to select multiple seeds?
I'm just guessing that in the future you will have different seeds/plants and the player might want to collect some in the stash box above. People just love to collect and anything that can make that faster the better. I came to a point my screen was full of seeds and clicking each single one to either collect or plant was eventually tedious. If i could select a bunch and say plant a bunch at same time that be nice.
I don't know if it's just me but by instinct (only). I thought I could hold down click like Command and conquer and select a bunch. I feel it's just natural.
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