Before I start I would like you to know what 64-bit means?
Cutting long story short, YES, we indeed need an 64-bit processing power.
First of all Android versions upto Kitkat doesn’t have anything to do with 64-bit, they don’t have any support for an 64-bit architect. Secondly, there is not a single app on Google Play which is built for 64-bit. Thirdly Google with its Android Lollipop is bringing in 64-Bit support.
Basic Android phones with 1 gigs of RAM or 2 gigs of RAM has nothing to do with 64-bit. It may increase some performance, as its the latest hardware inside, but the old flagship phones like Samsung Galaxy S4, Samsung Galaxy Note 2, Sony Xperia Z1, Sony Xperia Z2, HTC One (M7), HTC Butterfly S, etc. will still be the best choice as you can have them for similar prices or even less.
Please note Google has designed its Android Lollipop for ARMV8 Architecture, it will work with other Architectures but not as good as ARMV8.Companies like Micromax, Lava, Xolo, Karbonn, Intex, etc. may not use that Architecture. I even doubt on Samsung on this, as it keeps double standards towards Indian.
Qualcomm already launched 64-bit processors, i.e. Snapdragon 410, 415, 610, etc. The main flagship Snapdragon 810 is yet to launch. nVidia is also working on 64-bit processor Tegra K1.
HTC already launched 3 devices with 64-bit processor (ARMV8)
1. HTC Desire 510
2. HTC Desire 820Q
3. HTC Desire 820
To know more about them Google it.
1. Will the developers be developing 64-bit compatible apps?
2. Is 64-bit Android smartphone for me?
That depends. Using 64-bit with less than 4GB RAM is like using Walkman in times of Smartphones & iPods.
3. In future, will all the Android phones be having 64-bit processors?
YES, from budget friendly to flagships all will be having it.
You been using 32-bit Smartphones for all these years, so does 64-bit means double speed? This is the question everyone will ask and question themselves. This is a very important point on which the marketers will advertise its products. We have already seen previous marketing strategies like MORE MEGAPIXELS, MORE CORES, LARGER DISPLAY, etc. Coming back to the question does 64-bit means double speed? Read it here.