In reply to Lankyman:
I don’t use a phone as a hotspot very often now, but some thoughts, which maybe out of date, just in case they is important to you -
1. Phone battery will be used when it’s a hotspot so drain quicker.
2. You may not have full use of the phone for other things when it’s a hotspot (this may not apply to modern phones nowadays). On the other hand a separate data hotspot would allow multiple devices to connect (including your phone and if you don’t need a lot of data for it by itself when near the hotspot it could be cheaper overall?).
3. Some contracts used to ban tethering from phones completely (had to have a certain dearer contract to get tethering), or some permitted but slowed down data (throttling) if used too much in a certain time period and/or after a certain total usage in the contract (more so with “unlimited data”). Just check T&Cs before you sign up to see if it meets your needs.
4. Some companies allow unused data to roll over to next period if your usage varies a lot; might allow a smaller/cheaper package overall?). I “think” ID mobile do roll over ], as do EE, Sky, O2 and maybe others.