If you pin to IPFS and then use a public http gateway like https://cloudflare-ipfs.com, which caches and distributes via their CDN, you'll have a good CDN alternative.
If you just use IPFS directly with a non-CDN'd, non-cached http gateway, the latency will probably be prohibitive for regular web stuff.
Yes, definitely. I mean, you certainly get better bandwidth and latency depending on popularity and geographic diversity of seeders, and there are even youtube-alternative websites that host videos on IPFS. But for something like browsing from one page to the next, where the payload is small and you want <200ms latency, I think just the DHT lookup might already put you above that budget. I'm guessing though, haven't made any measurements.
In torrent when you download something you also announce yourself as a seeder. In ipfs afaik you have to explicitly pin something in order for your peer to be announced as a provider.
This means that even if your content in ipfs is popular it won’t be fast.
I should add, since you didn't specifically mention web stuff, that it _can_ be used as a CDN for stuff that is less latency-sensitive, like software package managers. That is in fact, the main focus of 2019 for Protocol Labs, the company behind IPFS.
If you just use IPFS directly with a non-CDN'd, non-cached http gateway, the latency will probably be prohibitive for regular web stuff.