I bet it was a lovely treat for him! My old hamster Bramble used to like a bit of roast beef sometimes when we were having it. But I'd agree with the others than every day would be too much. It's difficult to freeze hamster-sized portions - they really don't need that much, just a piece about the size of their ear - so I tend to just give them a bit of meat or fish if we are having something that would be suitable for them. You can also feed plain salmon, white fish, even tinned sardines or tuna as long as they're in spring water not brine, oil or any sauce.
When it comes to safety, every time meat either thaws or cools down, it can potentially grow toxic bacteria. That's why you can only reheat food a certain number of times, even if it's heated to piping hot every time, and shouldn't keep thawing and refreezing things. It's generally safe to feed meat that's been cooked, quickly cooled and frozen once, then thawed but the risk is further reduced if you heat it again thoroughly. Personally I also prefer to only give meat (and egg) when the hamster is already awake because I don't want it sitting in the cage growing bacteria for too long.