No you should support physical.

You might not want to trade or resell this specific game, but in other cases when you do want to, you wont have the option to if digital prevails over physical.

Over here in the UK, they are almost always more expensive on PSN than physical retailers anyway.

Just as an example, look at everyone raging asking for refunds on GTA V PC.

I got a refund on my Halo MCC digital copy by calling microsoft.

I'd rather buy physical. Games these days are getting too big and ISPs are getting too greedy with data caps and bandwidth. Games will never go completely digital worldwide for that reason. Another reason is HDD space (at least on the XB1, I'm not sure about the PS4).

I have a large amount of Digital games but i still prefer physical copies. I worry that if my HDD crashes 10 years from now that i won't have the option to re-download them to a new HDD. If that happens I'm out the games and my money. If you have physical and your rig goes down all you have to do is buy a new rig and you still have your games (although you may also miss out on patches if it is a significant amount of time after release).

Your purchase are tied to your PSN or Xbox live account. You can always re-download.

This is exactly what I do. It helps save money here, and there.

And if one of those services ends?

physical all the way

I just did this and it still works. Disconnected from the internet, signed out if PSN, I can still play my digital games (bloodborne)

In general: both have their pros and con's. Digital is so convenient and sometimes cheaper, physical has resell value.  I have mainly gone digital because I can get stuff day 1 without putting pants on. 

Do you think it will still be available for download 10 years from now, 20 years from now? Eventually you will lose access to digital content, they will not host it forever.