Having a Wi-Fi remote like Foobar2000 Copilot becomes especially useful in scenarios where you want to control a PC based Foobar2000 audio server while moving about - not tethered to a PC keyboard and screen.
Home Theater PC Scenario
You may have a home theater PC (HTPC) connected to your wall mounted flat screen TV with audio either output to your AV receiver sound system or driving any other specialized audio setups you may have.
You may have a wireless keyboard/track pad tied to your PC and you may use the large wall mounted TV as your PC monitor to gain some additional degree of mobility while listening to your music. You can go with smaller wireless keyboard/track pad options to make that a little more doable, but you still have to have that keyboard within arm's reach and the TV screen in view.
Using Foobar2000 Copilot on your Windows phone makes for a much simpler and easier setup for controlling your Foobar2000 server. You are trading off your larger TV screen for your smaller Windows Phone screen, but you can then control your audio server from anywhere in your home or office.
Foobar2000 Copilot does allow you to view long track title names, say if you are using WAV files for audio, by allowing horizontal scroll for viewing. If you are using other file formats, such as MP3, FLAC, which support embedded tags for album, artist, etc., viewing on Foobar2000 Copilot should be ample.
Bluetooth Speakers, Headphones
There are many Bluetooth headphones and small portable speakers available. There are also various Bluetooth transmitter/receiver adapters for RCA or 3.5mm speaker hookups if you want to use an existing pair of non-Bluetooth speakers.
There are also high gain antenna options available for Bluetooth transmitters to increase range (some over 100'). But with Bluetooth 4.0 and depending on the particulars of your environment, you might get a 40-50' range or sometimes only a 20-30' range…
Wearing a pair of Bluetooth headphones, you can more freely move about, with audio streamed from your Foobar2000 server and remotely controlled using Foobar2000 Copilot on your Windows phone.
With a portable battery powered Bluetooth speaker, you can conveniently move it around different rooms of your home and have your Foobar2000 audio server stream audio to it via Bluetooth. You control playback of that audio using Foobar2000 Copilot running on your phone, talking Wi-Fi to your Foobar2000 server PC.
For more details on how to stream audio from Foobar2000 to your Bluetooth output devices, see : Streaming to Bluetooth headphones or speakers
Audio quality varies depending on the particulars of your Bluetooth hardware, but also on what software audio device driver profiles you have installed and are using. There are various Bluetooth software stacks available for Windows.
Internet Radio
There was and still is a time where stations broadcast on shortwave radio or the regular radio broadcast bands, but also today many stations are additionally 'broadcasting' on the Internet.
You may mainly use Foobar2000 to play music from your personal music library, but it's also capable of streaming audio from Internet radio stations.
For details on how to do this , see : Adding an Internet Radio Station to Foobar2000
This is one of the advantages of using a PC based music server which is Internet connected.
Multiple, Smaller Home Servers
To process audio in Foobar2000 on a PC does not require a very powerful PC setup as you would need if processing video or doing gaming. You can purchase fairly low cost, small form factor PCs, some palm-sized, and setup separate audio home servers - say one in a bedroom, one in a den…
You could store your music files centrally on a network drive, accessible to all your home PCs. Also external USB drives have increased in capacity and decreased in cost, so you could optionally store your entire music library on an external USB drive and take it with you, when you are on the go.
Foobar2000 Copilot allows you to store multiple server definitions and allows you to switch quickly between them.
Multiple Foobar2000 Copilot Remotes
Foobar2000 Copilot runs fine on lower cost Windows phones such as the Nokia 520/635, albeit on smaller screens versus other more costly Windows phones such as the 6" Nokia 1520. The Nokia 520 and 635 can be bought off contract relatively inexpensively (typically < $50).
Of the two, I'd recommend the Nokia 635, being newer and having a little bigger, better screen and a faster processor.
So you might buy a lower cost phone, like the Nokia 520 or 635, and not use it as a phone at all, but as a Wi-Fi Copilot remote for general use around your home.
You can have multiple Foobar2000 Copilot remotes connected to the same Foobar2000 audio server at the same time - so multiple family members or home guests could be simultaneously connected to the same server.