Smart lady.
Not 100% certain what you mean by the tech still coming along. Some early transmitters have been problematic. Some brands of transmitters seem to still have some issues. The PPS transmitters that work with the Perdix seem to be rock solid. I've got 3 of them, and they've all been quite reliable. For the most part, the tech on these have been quite stable. Some have added colors to indicate tank pressure, some add battery saving features (solution in search of a problem, IMHO) the Swift added capability of varying broadcast interval, but apart from that no significant changes in a while.
Garmin now seems to be pushing the envelope a bit with being able to send text messages via the transceiver. Sending text messages is quite a bit different than sending music.
She shouldn't need to monitor you at all, but that's another discussion. If you are diligent about checking your gas levels, you should be able to communicate remaining gas info without the need for a nanny on your back. I regularly dive with my kids. They have transmitters as well, but I don't have theirs programmed into my computer. I simply signal them and have them let me know their gas level.
Her concerns about your old SPG failing may have more merit. It's a mechanical device. While failures are rare, they do happen. A failure of an SPG may go unnoticed. I've seen it happen before. Needle stuck at pretty close to full. I knew it couldn't be right, but if it stuck at a lower pressure, it may have gone unnoticed at first.
Depending on your dives, you will likely find that the computer and table do not agree. If you only do square dives, then they will. Otherwise, the computer will give you more time than the table. If you do charters, you'll probably start finding that they may require a computer.