I'm similar, in having a flip-phone and which is enough for me at the moment, but my issues with smart phones are mostly that I will be paying for something that I will not use so much, and where I much prefer a laptop for internet use. I think I would just get too frustrated looking at such a small screen and coping with how things are presented on such.
As to the intrusiveness, well I seem to manage my laptop without being too bothered by advertising, tracking, spamming, and such, mostly perhaps because I don't use social media, but also because I use enough software to control what they do, and I suspect such is available for smartphones too. But mainly I suppose it is down to what presence one has in cyber-space, and if one must be totally involved in such (social media being the obvious) then one might have to accept some level of intrusiveness.
