Thinking about mostly online video streaming services - Lightbox, Google Movies et al.
Possibly an Ethernet connected HTPC would give better quality than ChromeCast?
I also stream live radio quite a lot when working from home.
Not thinking about recording FTA TV as I have MySKy.
Local streaming would be from NAS and primarily be music with some viewing of video and photos.
I'll answer this from a different angle (and I assume when you say streaming you mean local files from a NAS/HDD/etc). If you are happy with the content you can get from online services, bearing in mind Netflix is cracking down on the likes of DNS blockers and VPN's and Hulu now needs a USA credit card to register, then yes, its a waste of time. Get an Apple TV, even the previous Version 3, and consume away (substitute Apple TV with any other device you like)
However if you find (like me) that the content made available to users in NZ is piss poor compared to what's on offer overseas, and you can get this content otherwise (Amazon Blu-rays/DVDs, torrents, usenet, friends with collections, etc) then no, its not a ware of time. A HTPC is still the single best way to consume local content. Every other option has some limitation, and there are multiple options in the HTPC software space from Plex (consume on almost any device) to Kodi (install and run) to JRiver where you can extract maximum video and sound quality.
Personally I am moving from the online services back to local content as the moves made by Netflix take a LOT of the WAF factor out of devices like Roku's, Apple TV's, etc. My current plans are either Apple TV 4 running InFuse for local content (only downside is the scrapping is done on the client, which can mean a delay getting that information when browsing folders, and the DTS/DD debacle of Apple's making); or finishing my NUC and running Kodi.