It may, or may not be a ploy and it will vary from time to time!
As a general rule (note 'general') points are of most value to upgrade on long haul. If you buy a ticket in Y and upgrade to a higher cabin, you will get more for the points as the airline has had some cash from you.
I have a small set of points from the old UK 'Air Miles' scheme that are now part of Avios. These are separate to the Avios of BA itself as they are different Avios! I have had them for over 10 years as they are not worth using. I have checked many times for European short haul - and I could use them and pay the tax - but it's better to pay directly for the flight.
The examples given above are good advice. I collect both BA and VS and have found them very useful for long haul upgrades and THEN they are good value as you also get more points for the basic Y fare that you bought. The other main guide line for such schemes is: Do not change your purchasing habits to get points. ONLY seek to gain points for a purchase that you were already making.
Whilst on the subject of Avios in particular (we weren't!) I have not seen an option to txfer 'Air Miles' Avios to BA Avios. Has anyone done this? My small collection could then join the big collection and be useful - which is why they probably don't want me to do that.
