Any drawbacks of setting 'store' option to false in string type field mappings?

Hello there.
I’m currently using Atlas Search in collection containing around 16M documents.
And it seems setting search index in this collection makes index size larger than the size of actual data.
So I look through the official document and it says

To reduce the index size and performance footprint, we recommend setting store to false .

Since I’m not using Highlight search terms, I thought setting ‘store’ option to false might help reduce the size of the index.
But the document’s description wasn’t very clear about any drawbacks of it, so I’m hesitating to change the option in my current index.
In my understanding, setting ‘store’ option to false makes not to store document text as well as the analyzed values in the index.
Wouldn’t it then be too slow when searching through the index every time?
What are the possible drawbacks of setting ‘store’ option to false in string type field mappings?

Hope anyone could help me understand this issue.
Please comment if my question was unclear.
Thanks in advance.