In general, and in my experience, consumer ITSP VoIP isn't reliable enough to depend on, for dial-up connection to an alarm monitoring company. VoIP service supplied by cable companies (well, at least Comcast; I can't vouch for the others) is very reliable, because, unlike pure-play ITSPs, they use a dedicated, managed network to provide the service (it doesn't travel over the public Internet). Alarm panels use an ancient protocol to transmit the messages, which has very limited accommodation for signal quality errors.
The major alarm monitoring companies recommended method of monitoring is now via either a 4G mobile data modem, or via a IP connection, or both, for redundancy.
You'll see a check-box on the OBiTALK website when configuring Google Voice, that enables that SP configuration to use with a security panel. However, this renders that Google Voice setup useless for regular voice calling.
No doubt, others will disagree, but personally, I'd rather pay for reliable monitoring than take my chances. Contact your alarm monitoring company for their recommended solution.