I assume from this that by streaming you are only thinking in terms of online from remote internet-based sources. Streaming also refers to playing music from your own locally stored music, e.g. stored on a computer or NAS (‘network attached storage’, essentially a streamlined specialised computer with often multiple hard disks), the music either being bought online and downloaded, or ‘ripped’ from CDs, or even from Vinyl.
Ultimately the local store potentially at least can be better quality, no risk of dropouts, yours to keep forever with no subscription, no reliance on remote operators remaining in business and stocking the music you like in perpetuity. Against that, online providers offer considerably more choice than most people can ever even consider owning, and lower immediate cost of access to lots of music.
That said, the two are not mutually exclusive. Any player capable of online streaming is likely to be able to stream from a local store (but the converse is not necessarily true), so starting online does not preclude also locally streaming, perhaps buying just things you like best and that you know you will always want.
As for the likes of Tidal, Qobuz, Spotify, etc., one significant difference is the range of music they have, some better suited to individuals’ tastes than others, so maybe before subscribing to one you might want to do some detailed searching of them all. Other differences include ease of browsing.and searching , though that can also be influenced by the software on the platform you choose.not all players are set up to access all online sources, so it is appropriate to do your research of content in particular before committing to one that offers only, say, Tidal.
There are also differences in sound quality available from the different online providers, E.g. Tidal offers something called ‘MQA’ that is alleged to enable you to stream hi res music with smaller file sizes, therefore coping better with low bandwidth connections, but it is a lossy compression and not everyone is impressed - though some people are (a search of this forum will bring up a range of views). IIRC Qobuz offers hi res streaming, though I also seem to recall that might not yet be up and running. I have been pleasantly surprised at how good Spotify’s free service sounds, even though only 320bps- plenty good enough for the purpose I use it, which is checking out new music (and if I like it I buy it, so no point my paying for a subscription service). However, the difference in sound quality between hi res and standard versions etc is often more to do with the mastering than the resolution, and it is not unknown for people to prefer the standard quality version.
As for gear, the options include a dedicated ‘streamer’, connected to a hifi system just like a CD player, or the ‘all-in-one’ approach like the Atom and Nova, or you can use a computer connected to a hifi DAC, preferably a specialist computer as an audio source in its own right optimised for sound quality, while the DAC could be a standalone one, or if you already have a CD player with a digital input you could set up that way, giving the lowest cost intro to try out online streaming services before committing.