I’m not a Tor expert, but IMO always using a local bridge is basically equivalent to having a Tor circuit of 2 hops, instead of 3. Thus, for one given circuit, if just the exit relay and the middle relay collude, they will know the source and the destination IP of the traffic.
Effectively you get no extra privacy from your entry relay if it’s always at your home.
However, to make a conclusion that the actual Tor user is behind that source address, the adversary would have to know that you do, in fact, use Tor in such a way, which most people don’t. I.e. they will know the IP address of the entry relay, but they won’t be sure if the real Tor client is behind that IP, or if it’s on a different IP, but is just connected through this entry node.
If Alice were to pick an entry relay that is always close to her home, the middle relay would know that the Tor user lives close to that entry relay. If Alice were to pick an exit relay that is always close to the destination, the middle relay would know that the destination is close to that exit relay.
IMO it would be safer to just run a relay at home, but not always use it as the entry node. This way your actual Tor client traffic will be mixed with your Tor relay’s traffic, making it hard to differentiate one from the other.
But again, I’m not an expert.