No, he was not effective
A good lawyer litigating a constitutional law case would know what the standards of review are for determining constitutionality (strict scrutiny, intermediate scrutiny, or rational basis review) and have an argument for which one applies. Giuliani appeared to be unfamiliar with these standards.
Quoting from an exchange between Giuliani and Judge Brann:
Brann: What standard of review should I apply, and why? What standard of review should I apply in this case —
Giuliani: On a motion to dismiss? I mean I think the normal one, which is that you, you have to deem the factual allegations to be correct, and even if they are correct, you have to find that there’s no merit, no legal merit, no legal theory on which we can get relief.
Brann: Well let me ask you then, are you arguing strict scrutiny should apply here?
Giuliani: No, the normal scrutiny should apply. If we had alleged fraud, yes. But this is not a fraud case.
Brann: …So if that’s the case, why don’t Secretary Boockvar’s and the counties satisfy the standard of review you’re talking about? If it’s not strict scrutiny, and it’s the standard of review you’re implying, why don’t their actions satisfy this?
Giuliani: I’m sorry, I don’t really understand the question, your honor.
Brann: Well this is how I would look at it. I would think that it’s a standard of review of strict scrutiny, potentially. You’re not sure that that’s the case. I’m not imposing my —
Giuliani: Maybe I don’t understand what you mean by “strict” —
Brann: Well, for strict scrutiny to apply, a fundamental right needs to be burdened, as I understand it. So how do the counties or Secretary Boockvar, on behalf of the commonwealth, burden the plaintiffs’ right to vote? How do they burden the right to vote?
The judge is basically giving Giuliani the answer here: he's challenging government action, so strict scrutiny would work in his favor, as it imposes the highest burden on the government to justify its action. The judge is even saying that he thinks strict scrutiny may apply. Despite that, Giuliani appears to have no idea what the judge is referring to, and is simply describing the standard for a motion to dismiss.
The government's lawyers were prepared for this question, as they should have been, and argued for rational-basis review, which favors the government. Had Giuliani argued competently, there could have been two sides to that argument instead of only one.