In my country it has suddenly become popular to use "gravitas" (weighed down with eggs) as if it means "importance". If I had used "gravitas" for "importance" above, would you have pictured an old book covered with insect eggs?
I think you're confusing:
'Gravitas' (weight/dignity) with 'Gravid' (weighed down with pregnancy/eggs)
As you can see, by carefully detailing each description they both have a relationship with weight (as with 'gravity')