Ohh, I see
When you're using the equal query is like you're doing this
SELECT * FROM collection_name WHERE attribute1='value1' AND attribute2='value2'
When you do it with search you'll get something like this
SELECT * FROM collection_name WHERE MATCH (attribute1) AGAINST ('search values' IN BOOLEAN MODE);
The different is that full text search works with MariaDB algorithm for extracting pieces of text from a large strings.
You read it about it here:
https://mariadb.com/kb/en/full-text-index-overview/
Also, a side note.
The different approach between equal and full text, is that full text is meant for data the need to be extracted from a large text and data that is not indexable.