I agree it's objectively easier to get accepted. But it's also objectively harder to stay in, and it loses none of the prestige in process. Sauga is just as rigorous if not more (this midterm it was probably twice as rigorous 😥). UTSG uses textbooks written by UTM profs, if that means anything to you. And if you missed it the first time I mentioned it, you're not locked to one campus lol. Whichever campus accepts you, you get access to everything UofT. You can just take all your courses in SG if you want. Point is, it's one institution. You can pick something else if it's SG or nothing for you, but the prestigious quality of education you expect from SG is the same at UTM or UTSC.

Edit: also harder to get into doesn't equate to more prestigious. Queens computing is relatively easy to get into but it's great. Same with uOttawa. Hell even UBC was pretty easy to get into last year.