How to decrypt Service Master Key and Database Master Key

I would like to make sure if this is the right procedure to decrypt Service Master Key and Database Master Key on SQL Server 2014 Enterprise. Here is my understanding.

(1) Restore Service Master Key

Restore Service Master Key
From File = 'Path_Of_Backup_Of_SMK'
Decryption By Password = 'Password_Of_Backup_Of_SMK'; 

(2) Restore Database Master Key

use <database>;
Restore Master Key
From File = 'Path_Of_Backup_Of_DMK'
Decryption By Password = 'Password_Of_Backup_Of_DMK'

(3) Drop DMK certification

use <database>;
Drop Certificate 'Name_Of_Certificate';

(4) Drop DMK

use <database>;
Open Master key Decryption by Password = 'Password_Of_DMK';
Drop Database Master Key;

If I decrypt SMK and DMK once, can't I restore database from Full/Differential/transaction backup files that were taken during DMK and SMK were configured on the database?

Is there any other concern to database management that can have impact from decrypting SMK and DMK?