My first thought was, wouldn’t this degrade the battery quicker? I see a possible future of ex-lease cars being sold with very degraded batteries. Not just because of V2G, but many people who lease not recharging and discharging batteries in a way that prolongs battery condition, as they may have the attitude of “won’t be my problem, I’ll be handing it back when it’s 3 years old” Of course similar could be said about ICE cars not being serviced, but I think it’s part of a lease agreement to do servicing.
Every battery has a maximum life cycle of charge/discharge, so will leave you to decide.
However when solid state batteries eventually become the norm in EV’s it ay well be a different kettle of fish.