Nothing would prevent other GA from getting them too, especially those who complain that they hate gliders/can’t see us/it’s our fault we can’t fit transponders (even for those gliders where it is not our fault, of which there are many) etc. – but I’m not holding my breath.
So I have to carry a completely separate bit of kit, displaying on a separate screen, to detect gliders... And then next year, the microlight community will decide they want to use a different technology with different standards and I have to go and buy/fit another piece of kit...
There's a perfectly good standard out there for this which is an ICAO standard. It's ADS-B over 1090ES which most large aircraft and an increasing number of light aircraft already have the equipment to use. The issue is surely only about the power required vs the range of the equipment -- I can't see anything about FLARM that improves the range to power over 1090ES. All the cost is in the certification and it's as easy to certify a light and low-power 1090ES transponder (or at least, ADS-B-out box) as it is to certify FLARM.