Right, but the Pixel 3a and 3a XL with Q beta 6 are able to have both SIM and eSIM simultaneously active with two signal strength meters and they can receive or make calls on either SIM without any special action on the user's part. This is known as Dual SIM, Dual Standby (DSDS).
The 3 and 3 XL did the same under Q beta 2 but then it was disabled again in beta 3.
What the 3 and 3 XL are doing currently is called Dual SIM, Single Standby (DSSS).