I don't consider "dumb" garage doors to be very secure to begin with. And In my case, the unlocked man door would probably be more attractive to thieves than my home made IoT garage door opener.
The "security" of my IoT automation stuff is of very little concern to me. Any sense that one was more secure before using IoT and less secure after, is mostly illusory (not to mention academic). If thieves/criminals target you, a dearth of internet connected devices will not cause them to pass you by. Glass still breaks, locks still get smashed, and doors still get jimmied.
And as far as toeholds into home networking... the WiFi router itself would be a far more attractive (and fairly well documented) point of failure. Especially for any competent gang of professional home hackers who've set up shop in your neighborhood.