VFR flight plan gives you zero flight following from an ATCO.
Your departure airport gets informed and your arrival. Everyone in the middle doesn't have a clue.
If and when some notices you not where you said you would be they will then have a look in the system to see if you submitted a flight plan. This could be mins if you were talking to an info service or hours if you Mrs phones the police the next day and says I haven't heard from them.
An IFR can be just as bad.If you drop out of CAS the UK like to dump everything to do with you and if the arrival tower doesn't ask where you are and dumps the strip you are in the same position as VFR.