Is it good idea to store mysql temporary tables in RAM instead of classic HDD?

there are two interesting tutorials on how to make mysql prefer RAM (tmpfs) instead of HDD:

shell> mkdir /tmp/mysqltmp
shell> chown mysql:mysql /tmp/mysqltmp
shell> id mysql
##NOTE: make sure you get the uid and gid for mysql
shell> vi /etc/fstab
## make sure this in in your fstab
tmpfs /tmp/mysqltmp tmpfs rw,uid=25,gid=26,size=2G,nr_inodes=10k,mode=0700 0 0
shell> mount /tmp/mysqltmp
shell> vi /etc/my.cnf #or the mysql config file for your server
## NOTE: inside the file add the following under [mysqld]
shell> service mysql restart


If MySQL is causing high I/O on HDD, %wait value is high and iotop -ao shows mysql processes as source of high disk usage, then it can be good idea to switch MySQL temporary tables storage from HDD to RAM..