Sorry if this is a dumb question but we are thinking about getting a smartwatch (Apple or Samsung) and wanted to know if any of these mobile providers will allow for use on this device?
Guy at JB HI FI said that they can only work with Voda/Telstra/Optus
Not quite.
eSims are currently offered by GoMo and Truphone (data only).
Telstra announced back in March they will allow MVNO's to sell eSIM's but so far it only Woolworths has integrated (with caveat, see below) - Aldi have been saying they will offer soon.
Woolworths Mobile apparently now offers esim as an upgrade in their app, but it does not yet have number sharing capacity (being worked on) so you would need 2 phone numbers, one for phone and one for watch.
eSIM isn’t currently offered by any MNVO's in Australia, so you will need a post-paid plan with the operators as advised by JB.