First example of the use of a variable in influxdb query should not use a regex query but a simple one. A first time influxdb user (like me) could think that the proper way to use variable in a dashboard template is to use regex query, but it's not true. Also "=~ /$region/" may be erroniously thought identical to "= '$region'" while instead "=~ /^$region$/" is identical to "= '$region'", and for that type of query is useless (if not slower) use a regex query.