5K coins for Gravebuster seeds? Don't think so!

Wondering if everyone gets offered the same three 5K coin- 20 seed packets every night? Not that it makes a hill of beans difference except in asking my question which is: 

After you get Gravebuster to exploding level, what would be the point of upgrading it any further? I passed on spending coins on this plant's seeds just as I have passed on spending coins to upgrade 7 plants in my arsenal who already have enough seeds to level up. 

I got up to 4.5 million coins using pinata party and have spent about 800k of them on upgrades now that im in the 50k - 75k upgrade cost for plants. 

Are there some seeds you won't buy or some plants you'll hold off on upgrading just because you now think it's not worth the coins?